Статті в журналах: "Metal oxide electrocatalyst"

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Sung, Yung-Eun, Heejong Shin, and Jae Jeong Kim. "(Digital Presentation) Design of Metal/Metal Oxide Nanomaterials for Highly Active, Selective, and Durable Electrocatalysts." ECS Meeting Abstracts MA2022-02, no. 42 (October 9, 2022): 1553. http://dx.doi.org/10.1149/ma2022-02421553mtgabs.

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Electrocatalysis is a key part of renewable energy conversion in the future energy system. Sustainable energy conversion and chemical production require catalyst structure with high activity, durability, and product selectivity. In general, nanoscale electrocatalysts suffer various degradation phenomena during electrocatalysis, which leads to critical performance loss. Recently, the various hybrid nanostructures (such as ordered structure, metal/carbon encapsulation, or metal/metal oxide) have been highly investigated to achieve promising catalytic performances and enhanced stabilities. In this presentation, we will cover three different types of nanomaterials as highly active and stable electrocatalysts for oxygen reduction reaction (ORR). First, the alloy nanoparticles with ordered structures exhibit novel catalytic properties from their unique electronic and geometric structures. In particular, Pt alloys with atomically ordered crystal structures have been found to largely improve both electrocatalytic activity and stability for ORR through increased electronic interaction between Pt and other transition metals. Similarly, we recently demonstrated that well-controlled Co-, Mn- and Fe-based ternary or binary oxide nanocatalysts have an exceptionally high ORR activity, in addition to the promising electrocatalytic stability. Therefore, it is very important to synthesize well-ordered alloy nanocrystals to obtain highly durable and active electrocatalysts with respect to their structural and compositional properties. Second, we will show the strategic employment of carbon shells on electrocatalyst surfaces to enhance stability in the electrochemical process. Carbon shells can beneficially shield catalyst surfaces from electrochemical degradation and physical agglomeration. Thus carbon shells can effectively preserve the initial active site structure during electrocatalysis. The carbon shell also provides a confined environment at interfaces, enabling unconventional electrochemical behaviors. Finally, we will suggest an effective strategy to construct metal/oxide interfaces, precisely modulating the metal/oxide interfacial interactions in the nanoscale. By controlling the interface and strain effect on catalytic activity, we can achieve high active and stable metal oxide systems for ORR. We would like to describe the details of the above results, for investigating structure-activity relationships in electrocatalytic processes. Only when we start to comprehend the fundamentals behind electrocatalysis on the structure and interface of metal/metal oxide nanocrystals, they can be further advanced to be sustainable in long-term device operation.

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Karuppiah, Chelladurai, Balamurugan Thirumalraj, Srinivasan Alagar, Shakkthivel Piraman, Ying-Jeng Jame Li, and Chun-Chen Yang. "Solid-State Ball-Milling of Co3O4 Nano/Microspheres and Carbon Black Endorsed LaMnO3 Perovskite Catalyst for Bifunctional Oxygen Electrocatalysis." Catalysts 11, no. 1 (January 7, 2021): 76. http://dx.doi.org/10.3390/catal11010076.

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Developing a highly stable and non-precious, low-cost, bifunctional electrocatalyst is essential for energy storage and energy conversion devices due to the increasing demand from the consumers. Therefore, the fabrication of a bifunctional electrocatalyst is an emerging focus for the promotion and dissemination of energy storage/conversion devices. Spinel and perovskite transition metal oxides have been widely explored as efficient bifunctional electrocatalysts to replace the noble metals in fuel cell and metal-air batteries. In this work, we developed a bifunctional catalyst for oxygen reduction and oxygen evolution reaction (ORR/OER) study using the mechanochemical route coupling of cobalt oxide nano/microspheres and carbon black particles incorporated lanthanum manganite perovskite (LaMnO3@C-Co3O4) composite. It was synthesized through a simple and less-time consuming solid-state ball-milling method. The synthesized LaMnO3@C-Co3O4 composite was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction spectroscopy, and micro-Raman spectroscopy techniques. The electrocatalysis results showed excellent electrochemical activity towards ORR/OER kinetics using LaMnO3@C-Co3O4 catalyst, as compared with Pt/C, bare LaMnO3@C, and LaMnO3@C-RuO2 catalysts. The observed results suggested that the newly developed LaMnO3@C-Co3O4 electrocatalyst can be used as a potential candidate for air-cathodes in fuel cell and metal-air batteries.

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Karuppiah, Chelladurai, Balamurugan Thirumalraj, Srinivasan Alagar, Shakkthivel Piraman, Ying-Jeng Jame Li, and Chun-Chen Yang. "Solid-State Ball-Milling of Co3O4 Nano/Microspheres and Carbon Black Endorsed LaMnO3 Perovskite Catalyst for Bifunctional Oxygen Electrocatalysis." Catalysts 11, no. 1 (January 7, 2021): 76. http://dx.doi.org/10.3390/catal11010076.

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Developing a highly stable and non-precious, low-cost, bifunctional electrocatalyst is essential for energy storage and energy conversion devices due to the increasing demand from the consumers. Therefore, the fabrication of a bifunctional electrocatalyst is an emerging focus for the promotion and dissemination of energy storage/conversion devices. Spinel and perovskite transition metal oxides have been widely explored as efficient bifunctional electrocatalysts to replace the noble metals in fuel cell and metal-air batteries. In this work, we developed a bifunctional catalyst for oxygen reduction and oxygen evolution reaction (ORR/OER) study using the mechanochemical route coupling of cobalt oxide nano/microspheres and carbon black particles incorporated lanthanum manganite perovskite (LaMnO3@C-Co3O4) composite. It was synthesized through a simple and less-time consuming solid-state ball-milling method. The synthesized LaMnO3@C-Co3O4 composite was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction spectroscopy, and micro-Raman spectroscopy techniques. The electrocatalysis results showed excellent electrochemical activity towards ORR/OER kinetics using LaMnO3@C-Co3O4 catalyst, as compared with Pt/C, bare LaMnO3@C, and LaMnO3@C-RuO2 catalysts. The observed results suggested that the newly developed LaMnO3@C-Co3O4 electrocatalyst can be used as a potential candidate for air-cathodes in fuel cell and metal-air batteries.

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4

Sharma, Shuchi, and Ranga Rao Gangavarapu. "(Digital Presentation) Synthesis and Promoting Activity of Gd₂O₃for Methanol Electro-Oxidation on Pt/C." ECS Meeting Abstracts MA2022-02, no. 50 (October 9, 2022): 2426. http://dx.doi.org/10.1149/ma2022-02502426mtgabs.

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One of the challenges in electrocatalysis is to design either an efficient non-noble electrocatalyst or improve the electrocatalytic activity of Pt/C by incorporating promoters such as metal oxides, carbides and nitrides. Rare earth metal oxides such as CeO2 have been explored to promote methanol electro-oxidation on Pt/C electrocatalyst. It has been noted that the synthesis method has profound effect on the physiochemical and in turn electrochemical properties of metal oxide promoted Pt/C electrocatalysts. This concept is tested on Gd2O3 promoted Pt/C. Gd2O3 is prepared by precipitation (GdO-PC) method and polymer assisted method (GdO-PL). The oxygen storage capacity (OSC) of this oxide is correlated with the electrochemical activity of Gd2O3-Pt/C. GdO-PC has higher OSC and can release surface oxygen much easier as compared to GdO-PL for methanol electro-oxidation on Pt. The Gd2O3-Pt/C catalysts are prepared with Gd2O3, Vulcan carbon and Pt-salt (equivalent to 20 wt% Pt) using microwave assisted polyol reflux method. The electrocatalytic activity of Gd2O3-Pt/C towards methanol oxidation has been carried out by cyclic voltammetry, CO stripping experiments, chronopotentiometry, and chronoamperometry methods in acidic media. The measurements show that Pt-GdO-PC/C performs better than Pt-(GdO-PL)/C) and commercial Pt/C. This indicates that the synthesis route of Gd2O3 particles is crucial for promoting methanol electro-oxidation. The first principle calculations show that there is a charge transfer from Gd2O3 to Pt. (GdO-PC). It is concluded that higher OSC and charge transfer from Gd2O3 to Pt work in tandem to weaken the Pt-CO bond and oxidise CO to CO2, thus reducing the CO poisoning and enhancing the activity of the oxide promoted electrocatalyst. Figure 1

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5

Klaas, Lutho, Mmalewane Modibedi, Mkhulu Mathe, Huaneng Su, and Lindiwe Khotseng. "Electrochemical Studies of Pd-Based Anode Catalysts in Alkaline Medium for Direct Glycerol Fuel Cells." Catalysts 10, no. 9 (August 26, 2020): 968. http://dx.doi.org/10.3390/catal10090968.

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This study investigates the most effective electrocatalyst for glycerol oxidation reaction (GOR) in alkaline medium for five synthesized electrocatalysts, Pd, PdNi, PdNiO, PdMn3O4 and PdMn3O4NiO, supported on multi-walled carbon nanotubes (MWCNTs) prepared using the polyol method. The particle size and crystalline size of the electrocatalysts were determined using HR-TEM and XRD techniques, respectively, while EDS was used to determine the elemental composition. XRD showed crystalline sizes ranging from 3.4 to 10.1 nm, while HR-TEM revealed particle sizes within the range of 3.4 and 7.2 nm. The electroactivity, electron kinetics and stability of the electrocatalysts towards glycerol in alkaline medium was evaluated using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA), respectively, while the electroactive surface area (ECSA) of the electrocatalysts was determined using cyclic voltammetry (CV). The metal oxide-based Pd electrocatalysts PdNiO and PdMn3O4 were the most electrochemically active, while the addition of the second metal oxide to the Pd electrocatalyst PdMn3O4NiO did not show any improvement. This was associated with this electrocatalyst having the highest particle and crystalline sizes.

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6

Luo, Hongmei, and Meng Zhou. "Oxide Films and Nanoparticles for Lithium Ion Battery and Oxygen Electrocatalyst Applications." ECS Meeting Abstracts MA2022-01, no. 38 (July 7, 2022): 1668. http://dx.doi.org/10.1149/ma2022-01381668mtgabs.

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The global energy crisis coupling with the consumption of fossil fuels and the associated environmental issues, has stimulated extensive interest in searching for clean, efficient and sustainable energy storage and conversion systems. In this talk we are going to introduce a novel chemical solution approach for epitaxial thin film deposition and oxide nanoparticle network synthesis. The use of water soluable polymer to bind the metal ions has several advantages. The formation of covalent complexes between the lone pairs on the nitrogen atoms of the polymer and the metal cations make it possible to prepare almost any metal polymer precursor solutions. The unique chemistry and processing design of this technique deliver stable and homogeneous solutions at a molecular level that allows epitaxial growth of high-quality thin films and oxide nanoparticle network materials. Oxygen electrocatalysis, including both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), dominates the performance of the devices. However, the sluggish kinetics of these two reactions limits their performance. Therefore, development of non-precious metal-based oxygen electrocatalysts is greatly demanded. Metal oxides have attracted extensive interest as alternative electrocatalysts due to their low price and good endurance under relatively high temperature, which can be doped with a wide range of cations attributed to their flexible compositions and structures, leading to easy manipulation of their electrocatalytic properties. We study the nanoscale engineering of perovskite oxides and layered oxides in energy conversion/storage devices and focus on the electrode catalyst design and fabrication for boosting ORR and OER electrocatalysis.

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7

LU, J. L., CHANGWEI XU, and SAN PING JIANG. "ELECTRO-OXIDATION OF ETHANOL ON NANOCRYSTALLINE Pd/C CATALYST PROMOTED WITH OXIDE IN ALKALINE MEDIA." International Journal of Nanoscience 08, no. 01n02 (February 2009): 203–7. http://dx.doi.org/10.1142/s0219581x09005864.

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Nanocrystalline Pd electrocatalyst promoted with transition metal oxide ( Co 3 O 4, NiO , and CoNiO x) is successfully synthesized on high surface carbon support by using intermittent microwave heating (IMH) method. The physical properties of the catalysts are characterized by XRD, TEM, and EDX. The results show that there is no significant microstructure change between Pd and Pd -oxide electrocatalysts and the particle sizes are in the range 5.8–3.9 nm. The linear sweep voltammogram and chronoamperometry results for the electro-oxidation of ethanol show that Pd -oxide/ C electrocatalysts exhibit much better electrochemical activity and stability as compared with pure Pd / C electrocatalyst. The results show that Pd – CoNiO x/ C exhibits the best stability and highest electro-oxidation activity, indicating the promising potential as an alternative electrocatalysts for the direct ethanol fuel cells.

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8

Knecht, Tawney A., Shannon W. Boettcher, and James E. Hutchison. "Electrochemistry-Induced Restructuring of Tin-Doped Indium Oxide Nanocrystal Films of Relevance to CO₂ Reduction." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 126521. http://dx.doi.org/10.1149/1945-7111/ac40ca.

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The electrochemical reduction of CO2 into fuels using renewable electricity presents an opportunity to utilize captured CO2. Electrocatalyst development has been a primary focus of research in this area. This is especially true at the nanoscale, where researchers have focused on understanding nanostructure-property relationships. However, electrocatalyst structure may evolve during operation. Indium- and tin-based oxides have been widely studied as electrocatalysts for CO2 reduction to formate, but evolution of these catalysts during operation is not well-characterized. Here, we report the evolution of nanoscale structure of precise tin-doped indium oxide nanocrystals under CO2 reduction conditions. We show that sparse monolayer nanocrystal films desorb from the electrode upon charging, but thicker nanocrystal films remain, likely due to an increased number of physical contacts. Upon applying a cathodic voltage of −1.0 V vs RHE or greater, the original 10-nm diameter nanocrystals are no longer visible, and instead form a larger microstructural network. Elemental analysis suggests the network is an oxygen-deficient indium-tin metal alloy. We hypothesize that this morphological evolution is the result of nanocrystal sintering due to oxide reduction. These data provide insights into the morphological evolution of tin-doped indium oxide nanocrystal electrocatalysts under reducing conditions and highlight the importance of post-electrochemical structural characterization of electrocatalysts.

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9

Nong, Hong Nhan, Hoang Phi Tran, Camillo Spöri, Malte Klingenhof, Lorenz Frevel, Travis E. Jones, Thorsten Cottre, et al. "The Role of Surface Hydroxylation, Lattice Vacancies and Bond Covalency in the Electrochemical Oxidation of Water (OER) on Ni-Depleted Iridium Oxide Catalysts." Zeitschrift für Physikalische Chemie 234, no. 5 (May 26, 2020): 787–812. http://dx.doi.org/10.1515/zpch-2019-1460.

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AbstractThe usage of iridium as an oxygen-evolution-reaction (OER) electrocatalyst requires very high atom efficiencies paired with high activity and stability. Our efforts during the past 6 years in the Priority Program 1613 funded by the Deutsche Forschungsgemeinschaft (DFG) were focused to mitigate the molecular origin of kinetic overpotentials of Ir-based OER catalysts and to design new materials to achieve that Ir-based catalysts are more atom and energy efficient, as well as stable. Approaches involved are: (1) use of bimetallic mixed metal oxide materials where Ir is combined with cheaper transition metals as starting materials, (2) use of dealloying concepts of nanometer sized core-shell particle with a thin noble metal oxide shell combined with a hollow or cheap transition metal-rich alloy core, and (3) use of corrosion-resistant high-surface-area oxide support materials. In this mini review, we have highlighted selected advances in our understanding of Ir–Ni bimetallic oxide electrocatalysts for the OER in acidic environments.

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10

Shinde, Pratik V., Rutuparna Samal, and Chandra Sekhar Rout. "Comparative Electrocatalytic Oxygen Evolution Reaction Studies of Spinel NiFe2O4 and Its Nanocarbon Hybrids." Transactions of Tianjin University 28, no. 1 (December 10, 2021): 80–88. http://dx.doi.org/10.1007/s12209-021-00310-x.

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AbstractElectrocatalytic oxygen evolution reaction (OER) is one of the crucial reactions for converting renewable electricity into chemical fuel in the form of hydrogen. To date, there is still a challenge in designing ideal cost-effective OER catalysts with excellent activity and robust durability. The hybridization of transition metal oxides and carbonaceous materials is one of the most effective and promising strategies to develop high-performance electrocatalysts. Herein, this work synthesized hybrids of NiFe2O4 spinel materials with two-dimensional (2D) graphene oxide and one-dimensional (1D) carbon nanotubes using a facile solvothermal approach. Electrocatalytic activities of NiFe2O4 with 2D graphene oxide toward OER were realized to be superior even to the 1D carbon nanotube-based electrocatalyst in terms of overpotential to reach a current density of 10 mA/cm2 as well as Tafel slopes. The NiFe2O4 with 2D graphene oxide hybrid exhibits good stability with an overpotential of 327 mV at a current density of 10 mA/cm2 and a Tafel slope of 103 mV/dec. The high performance of NiFe2O4 with 2D graphene oxide is mainly attributed to its unique morphology, more exposed active sites, and a porous structure with a high surface area. Thus, an approach of hybridizing a metal oxide with a carbonaceous material offers an attractive platform for developing an efficient electrocatalyst for water electrochemistry applications.

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11

Madan, Chetna, and Aditi Halder. "Engineering the Heterogeneous Interface of Sulphur Doped Nickel-Manganese Oxide for Efficient Overall Electrochemical Water Splitting." ECS Meeting Abstracts MA2022-01, no. 55 (July 7, 2022): 2310. http://dx.doi.org/10.1149/ma2022-01552310mtgabs.

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Electrochemical water splitting is the technique to utilize stochastic renewable sources for a continuous uninterrupted supply of energy through the production of hydrogen fuel. However, the performance of a water electrolyzer is limited due to the instability as well as larger overpotential associated with the current state of the electrocatalysts. Transition metal oxides show remarkable potential for catalyzing water electrolysis. Among transition metal oxides, binary transition metal compounds exhibit the forte to replace the expensive and scarce noble-metal electrocatalysts. The engineering of hetero-interfaces between sulphur doped nickel and manganese oxide nanostructures has been systematically presented in our study. The difference in morphology too affects the catalytic activity of the samples owing to variable electrolyte interaction. The strategic development of these hetero-interfaces wields the electrocatalyst its superior bifunctional activity for catalyzing oxygen evolution reaction at an overpotential as low as 300 mV at 20 mA cm-2 current density and hydrogen evolution reaction at 280 mV at 10 mA cm-2 current density. The catalyst also delivered a stable current density for a long-term durability study without any significant loss in the performance.

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Pham Hong, Hanh, Linh Do Chi, Phong Nguyen Ngoc, and Lam Nguyen Duc. "Synthesis and characterization of NiCoOx mixed nanocatalysts for anion exchanger membrane water electrolysis (AEMWE)." Vietnam Journal of Catalysis and Adsorption 9, no. 2 (July 31, 2020): 49–53. http://dx.doi.org/10.51316/jca.2020.028.

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Anion exchange membrane water electrolysis (AEMWE) is a well developed technology for the conversion of water into hydrogen and oxygen. AEMWE is still a developing technology. One of the major advantages of AEM water electrolysis is the replacement ofconventional noble metal electrocatalysts with low cost transition metal catalysts. In this study, we report characterization of NiCoOxmixed metallic oxides synthesized by the hydrolysis method as anodic electrocatalysts for AEMWE. The mechanisms of the thermal decomposition process of precursors to form mixed metallic oxide powders were studied by means of thermal gravity analysis (TGA), X-ray diffraction (XRD) while transmission electron microscopy (TEM) were used to evaluate the crystallographic structure, morphology and size of catalyst particles. The surface reactivity and stability of these oxides was investigated by cyclic voltammetry (CV) electrochemical method in solution of 1 M KOH. Based on the given results, the good anodic electrocatalyst was found.

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13

Faisal, Shaikh Nayeem, Enamul Haque, Nikan Noorbehesht, Hongwei Liu, Md Monirul Islam, Luba Shabnam, Anup Kumar Roy, et al. "A quadrafunctional electrocatalyst of nickel/nickel oxide embedded N-graphene for oxygen reduction, oxygen evolution, hydrogen evolution and hydrogen peroxide oxidation reactions." Sustainable Energy & Fuels 2, no. 9 (2018): 2081–89. http://dx.doi.org/10.1039/c8se00068a.

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14

Dymerska, Anna, Wojciech Kukułka, Marcin Biegun, and Ewa Mijowska. "Spinel of Nickel-Cobalt Oxide with Rod-Like Architecture as Electrocatalyst for Oxygen Evolution Reaction." Materials 13, no. 18 (September 4, 2020): 3918. http://dx.doi.org/10.3390/ma13183918.

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The renewable energy technologies require electrocatalysts for reactions, such as the oxygen and/or hydrogen evolution reaction (OER/HER). They are complex electrochemical reactions that take place through the direct transfer of electrons. However, mostly they have high over-potentials and slow kinetics, that is why they require electrocatalysts to lower the over-potential of the reactions and enhance the reaction rate. The commercially used catalysts (e.g., ruthenium nanoparticles—Ru, iridium nanoparticles—Ir, and their oxides: RuO2, IrO2, platinum—Pt) contain metals that have poor stability, and are not economically worthwhile for widespread application. Here, we propose the spinel structure of nickel-cobalt oxide (NiCo2O4) fabricated to serve as electrocatalyst for OER. These structures were obtained by a facile two-step method: (1) One-pot solvothermal reaction and subsequently (2) pyrolysis or carbonization, respectively. This material exhibits novel rod-like morphology formed by tiny spheres. The presence of transition metal particles such as Co and Ni due to their conductivity and electron configurations provides a great number of active sites, which brings superior electrochemical performance in oxygen evolution and good stability in long-term tests. Therefore, it is believed that we propose interesting low-cost material that can act as a super stable catalyst in OER.

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15

Mugheri, Abdul Qayoom, Aneela Tahira, Umair Aftab, Muhammad Ishaq Abro, Adeel Liaquat Bhatti, Shahid Ali, Mazhar Ali Abbasi, and Zafar Hussain Ibupoto. "A Low Charge Transfer Resistance CuO Composite for Efficient Oxygen Evolution Reaction in Alkaline Media." Journal of Nanoscience and Nanotechnology 21, no. 4 (April 1, 2021): 2613–20. http://dx.doi.org/10.1166/jnn.2021.19091.

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An efficient, simple, environment-friendly and inexpensive cupric oxide (CuO) electrocatalyst for oxygen evolution reaction (OER) is demonstrated. CuO is chemically deposited on the porous carbon material obtained from the dehydration of common sugar. The morphology of CuO on the porous carbon material is plate-like and monoclinic crystalline phase is confirmed by powder X-ray diffraction. The OER activity of CuO nanostructures is investigated in 1 M KOH aqueous solution. To date, the proposed electrocatalyst has the lowest possible potential of 1.49 V versus RHE (reversible hydrogen electrode) to achieve a current density of 20 mA/cm2 among the CuO based electrocatalysts and has Tafel slope of 115 mV dec-1. The electrocatalyst exhibits an excellent long-term stability for 6 hours along with significant durability. The enhanced catalytic active centers of CuO on the carbon material are due to the porous structure of carbon as well as strong coupling between CuO–C. The functionalization of metal oxides or other related nanostructured materials on porous carbon obtained from common sugar provides an opportunity for the development of efficient energy conversion and energy storage systems.

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Bhardwaj, Shiva, and Ram K. Gupta. "Highly Efficient and Cost-Effective Electrocatalysts Using Nickel-Based Metal-Organic Frameworks for Water Splitting." ECS Meeting Abstracts MA2022-02, no. 49 (October 9, 2022): 1941. http://dx.doi.org/10.1149/ma2022-02491941mtgabs.

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The low-cost nickel compound is one of the most effective electrocatalysts among the transition metals-based electrocatalysts. Therefore, understanding the electroactivity of nickel-based metal-organic frameworks (MOFs) plays a vital role in green energy production via hydrogen and oxygen evolution reactions. The demand for green and efficient energy devices is increasing rapidly and fuels cells could be one of the solutions for such requirements. This work introduces the use of MOF-derived nickel hydroxide and oxide as highly efficient electrocatalysts. The electrocatalysts were synthesized using a hydrothermal method at different growth temperatures (140, 160, and 180 °C). Glutaric acid was used as an organic ligand. The MOF-based nickel hydroxide was converted to nickel oxide via a facile calcination process at 350 °C. The best sample of MOF-derived nickel oxide (160 °C) showed an oxygen evolution overpotential of 394 mV at 10 mA/cm2 with a Tafel slope of 73 mV/dec. The unique structure of MOF-derived nickel hydroxide provides more electroactive sites. The shorter pathway for ion transference reduces the overpotential to 330 mV at 10 mA/cm2 with the lowest Tafel slope of 107 mV/dec. The best MOF-based nickel oxide electrocatalyst for hydrogen evolution reaction required 103 mV to deliver 10 mA/cm2. On the other hand, MOF-based nickel hydroxide needed 189 mV of overpotential to reach 10 mA/cm2. The stability of the prepared electrocatalysts was tested using cyclic linear voltammetry and chronoamperometry. Both measurements showed high electrocatalytic stability of the prepared samples for over 1,000 cycles of linear voltammetry and 24 hrs of chronoamperometry test. Our research provides cost-effective and highly efficient electrocatalysts for green energy production.

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Jiménez-Morales, Ignacio, Sara Cavaliere, Deborah Jones, and Jacques Rozière. "Strong metal–support interaction improves activity and stability of Pt electrocatalysts on doped metal oxides." Physical Chemistry Chemical Physics 20, no. 13 (2018): 8765–72. http://dx.doi.org/10.1039/c8cp00176f.

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Lu, Song, Fengliu Lou, and Zhixin Yu. "Recent Progress in Two-Dimensional Materials for Electrocatalytic CO2 Reduction." Catalysts 12, no. 2 (February 17, 2022): 228. http://dx.doi.org/10.3390/catal12020228.

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Electrocatalytic CO2 reduction (ECR) is an attractive approach to convert atmospheric CO2 to value-added chemicals and fuels. However, this process is still hindered by sluggish CO2 reaction kinetics and the lack of efficient electrocatalysts. Therefore, new strategies for electrocatalyst design should be developed to solve these problems. Two-dimensional (2D) materials possess great potential in ECR because of their unique electronic and structural properties, excellent electrical conductivity, high atomic utilization and high specific surface area. In this review, we summarize the recent progress on 2D electrocatalysts applied in ECR. We first give a brief description of ECR fundamentals and then discuss in detail the development of different types of 2D electrocatalysts for ECR, including metal, graphene-based materials, transition metal dichalcogenides (TMDs), metal–organic frameworks (MOFs), metal oxide nanosheets and 2D materials incorporated with single atoms as single-atom catalysts (SACs). Metals, such as Ag, Cu, Au, Pt and Pd, graphene-based materials, metal-doped nitric carbide, TMDs and MOFs can mostly only produce CO with a Faradic efficiencies (FE) of 80~90%. Particularly, SACs can exhibit FEs of CO higher than 90%. Metal oxides and graphene-based materials can produce HCOOH, but the FEs are generally lower than that of CO. Only Cu-based materials can produce high carbon products such as C2H4 but they have low product selectivity. It was proposed that the design and synthesis of novel 2D materials for ECR should be based on thorough understanding of the reaction mechanism through combined theoretical prediction with experimental study, especially in situ characterization techniques. The gap between laboratory synthesis and large-scale production of 2D materials also needs to be closed for commercial applications.

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Guo, Feng, Hui Yang, Lingmei Liu, Yu Han, Abdullah M. Al-Enizi, Ayman Nafady, Paul E. Kruger, Shane G. Telfer, and Shengqian Ma. "Hollow capsules of doped carbon incorporating metal@metal sulfide and metal@metal oxide core–shell nanoparticles derived from metal–organic framework composites for efficient oxygen electrocatalysis." Journal of Materials Chemistry A 7, no. 8 (2019): 3624–31. http://dx.doi.org/10.1039/c8ta11213d.

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Lin, Songmin, Yuan Yu, Dongfeng Sun, Fangyou Meng, Wenhui Chu, Jie Ren, Linyin Huang, Qingmei Su, Shufang Ma, and Bingshe Xu. "NiS₂ Nanoparticles Grown on Reduced Graphene Oxide Co-Doped with Sulfur and Nitrogen for Enhanced Hydrogen Evolution Reaction in Acid Media." Journal of The Electrochemical Society 169, no. 1 (January 1, 2022): 016518. http://dx.doi.org/10.1149/1945-7111/ac4c76.

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NiS2 nanoparticle electrocatalysts grown on sulfur and nitrogen co-doped reduced graphene oxide (NiS2/S,N-rGO) were explored. Since the hybrid catalyst of NiS2/S,N-rGO had a large surface area and high conductivity, it demonstrated outstanding electrocatalytic properties. This NiS2/S,N-rGO hybrid electrocatalyst required only 95 mV overvoltage to reach the current density of 10 mA cm−2 in hydrogen evolution reaction (HER) in acidic solution. In addition, the 5000 cycles test experiment showed the excellent HER electrochemical stability of the NiS2/S,N-rGO catalyst. This work also provided new strategies for increasing the catalytic activity of non-precious metal electrocatalysts.

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21

Mehek, Rimsha, Naseem Iqbal, Tayyaba Noor, Zahid Ali Ghazi, and Muhammad Umair. "Metal–organic framework derived vanadium oxide supported nanoporous carbon structure as a bifunctional electrocatalyst for potential application in metal air batteries." RSC Advances 13, no. 1 (2023): 652–64. http://dx.doi.org/10.1039/d2ra06688b.

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In this study, highly active vanadium metal organic framework (V-MIL-101) derived nanoporous vanadium oxide/carbon composite (NVC-900) is prepared and tested as a bifunctional electrocatalyst for metal air batteries.

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22

Jia, Lisha, Pawel Wagner, and Jun Chen. "Electrocatalyst Derived from NiCu–MOF Arrays on Graphene Oxide Modified Carbon Cloth for Water Splitting." Inorganics 10, no. 4 (April 13, 2022): 53. http://dx.doi.org/10.3390/inorganics10040053.

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Electrocatalysts are capable of transforming water into hydrogen, oxygen, and therefore into energy, in an environmentally friendly and sustainable manner. However, the limitations in the research of high performance catalysts act as an obstructer in the development of using water as green energy. Here, we report on a delicate method to prepare novel bimetallic metal organic framework derived electrocatalysts (C–NiCu–BDC–GO–CC) using graphene oxide (GO) modified carbon cloth as a 3D flexible and conductive substrate. The resultant electrocatalyst, C–NiCu–BDC–GO–CC, exhibited very low electron transfer resistance, which benefited from its extremely thin 3D sponge-like morphology. Furthermore, it showed excellent oxygen evolution reaction (OER) activity, achieving 10 mA/cm2 at a low overpotential of 390 mV in 1 M KOH electrolyte with a remarkable durability of 10 h.

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23

Zheng, Shasha, Xiaotian Guo, Huaiguo Xue, Kunming Pan, Chunsen Liu, and Huan Pang. "Facile one-pot generation of metal oxide/hydroxide@metal–organic framework composites: highly efficient bifunctional electrocatalysts for overall water splitting." Chemical Communications 55, no. 73 (2019): 10904–7. http://dx.doi.org/10.1039/c9cc06113d.

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The metal oxide/hydroxide@MOF composites have been regarded as a very promising electrocatalyst due to their facile one-step hydrothermal synthesis strategy, high electrocatalytic activity, and excellent cycling stability.

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24

Hossain, SK, Junaid Saleem, SleemUr Rahman, Syed Zaidi, Gordon McKay, and Chin Cheng. "Synthesis and Evaluation of Copper-Supported Titanium Oxide Nanotubes as Electrocatalyst for the Electrochemical Reduction of Carbon Oxide to Organics." Catalysts 9, no. 3 (March 25, 2019): 298. http://dx.doi.org/10.3390/catal9030298.

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Анотація:

Carbon dioxide (CO2) is considered as the prime reason for the global warming effect and one of the useful ways to transform it into an array of valuable products is through electrochemical reduction of CO2 (ERC). This process requires an efficient electrocatalyst with high faradaic efficiency at low overpotential and enhanced reaction rate. Herein, we report an innovative way of reducing CO2 using copper-metal supported on titanium oxide nanotubes (TNT) electrocatalysts. The TNT support material was synthesized using alkaline hydrothermal process with Degussa (P-25) as a starting material. Copper nanoparticles were anchored on the TNT by homogeneous deposition-precipitation method (HDP) with urea as precipitating agent. The prepared catalysts were tested in a home-made H-cell with 0.5 M NaHCO3 aqueous solution in order to examine their activity for ERC and the optimum copper loading. Continuous gas-phase ERC was carried out in a solid polymer electrolyte (SPE) reactor. The 10% Cu/TNT catalysts were employed in the gas diffusion layer (GDL) on the cathode side with Pt-Ru/C on the anode side. Faradaic efficiencies for the three major products namely methanol, methane, and CO were found to be 4%, 3%, and 10%, respectively at −2.5 V with an overall current density of 120 mA/cm2. The addition of TNT significantly increased the catalytic activity of electrocatalyst for ERC. It is mainly attributed to their better stability towards oxidation, increased CO2 adsorption capacity and stabilization of the reaction intermediate, layered titanates, and larger surface area (400 m2/g) as compared with other support materials. Considering the low cost of TNT, it is anticipated that TNT support electrocatalyst for ECR will gain popularity.

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25

Govindhan, Maduraiveeran, Brennan Mao, and Aicheng Chen. "Novel cobalt quantum dot/graphene nanocomposites as highly efficient electrocatalysts for water splitting." Nanoscale 8, no. 3 (2016): 1485–92. http://dx.doi.org/10.1039/c5nr06726j.

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26

Franco, Ana, Manuel Cano, Juan J. Giner-Casares, E. Rodríguez-Castellón, Rafael Luque, and Alain R. Puente-Santiago. "Boosting the electrochemical oxygen reduction activity of hemoglobin on fructose@graphene-oxide nanoplatforms." Chemical Communications 55, no. 32 (2019): 4671–74. http://dx.doi.org/10.1039/c9cc01625b.

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Анотація:

A metal-free oxygen reduction reaction (ORR) electrocatalyst with outstanding performance was obtained through an easy and one-pot synthesis of hemoglobin functionalized fructose@graphene-oxide (GO) nanocomposites.

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27

Devi, Hemam Rachna, Omeshwari Yadorao Bisen, Zhong Chen, and Karuna Kar Nanda. "Carbon Nanostructures-Transition Metal Oxide Hybrid As Bifunctional Electrocatalyst." ECS Meeting Abstracts MA2021-01, no. 38 (May 30, 2021): 1238. http://dx.doi.org/10.1149/ma2021-01381238mtgabs.

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28

Wu, Qian, Hao Wang, Shiying Shen, Baibiao Huang, Ying Dai, and Yandong Ma. "Efficient nitric oxide reduction to ammonia on a metal-free electrocatalyst." Journal of Materials Chemistry A 9, no. 9 (2021): 5434–41. http://dx.doi.org/10.1039/d0ta11209g.

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29

Liu, Guangsheng, Kunyapat Thummavichai, Xuefeng Lv, Wenting Chen, Tingjun Lin, Shipeng Tan, Minli Zeng, Yu Chen, Nannan Wang, and Yanqiu Zhu. "Defect-Rich Heterogeneous MoS2/rGO/NiS Nanocomposite for Efficient pH-Universal Hydrogen Evolution." Nanomaterials 11, no. 3 (March 8, 2021): 662. http://dx.doi.org/10.3390/nano11030662.

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Анотація:

Molybdenum disulfide (MoS2) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS2-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS2, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)2 nanowires as the nickel source. The MoS2/rGO/NiS-5 of optimal formulation in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm−2 (denoted as η10), respectively. The excellent HER performance of the MoS2/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS2/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst.

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30

Sapner, Vijay S., Balaji B. Mulik, Renuka V. Digraskar, Shankar S. Narwade, and Bhaskar R. Sathe. "Enhanced oxygen evolution reaction on amine functionalized graphene oxide in alkaline medium." RSC Advances 9, no. 12 (2019): 6444–51. http://dx.doi.org/10.1039/c8ra10286d.

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Анотація:

Metal free tyramine functionalized graphene oxide (T-GO) is a promising electrocatalyst for oxygen evolution reaction (OER) in alkaline medium having high activity and stability, resulting from the tyramine active sites.

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31

Cheng, Yi, Shuo Dou, Martin Saunders, Jin Zhang, Jian Pan, Shuangyin Wang, and San Ping Jiang. "A class of transition metal-oxide@MnOx core–shell structured oxygen electrocatalysts for reversible O2 reduction and evolution reactions." Journal of Materials Chemistry A 4, no. 36 (2016): 13881–89. http://dx.doi.org/10.1039/c6ta04758k.

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32

Yu, Jiemei, Taizhong Huang, Zhankun Jiang, Min Sun, and Chengchun Tang. "Synthesis and Characterizations of Zinc Oxide on Reduced Graphene Oxide for High Performance Electrocatalytic Reduction of Oxygen." Molecules 23, no. 12 (December 6, 2018): 3227. http://dx.doi.org/10.3390/molecules23123227.

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Electrocatalysts for the oxygen reduction (ORR) reaction play an important role in renewable energy technologies, including fuel cells and metal-air batteries. However, development of cost effective catalyst with high activity remains a great challenge. In this feature article, a hybrid material combining ZnO nanoparticles (NPs) with reduced graphene oxide (rGO) is applied as an efficient oxygen reduction electrocatalyst. It is fabricated through a facile one-step hydrothermal method, in which the formation of ZnO NPs and the reduction of graphene oxide are accomplished simultaneously. Transmission electron microscopy and scanning electron microscopy profiles reveal the uniform distribution of ZnO NPs on rGO sheets. Cyclic voltammograms, rotating disk electrode and rotating ring disk electrode measurements demonstrate that the hierarchical ZnO/rGO hybrid nanomaterial exhibits excellent electrocatalytic activity for ORR in alkaline medium, due to the high cathodic current density (9.21 × 10−5 mA/cm2), positive onset potential (−0.22 V), low H2O2 yield (less than 3%), and high electron transfer numbers (4e from O2 to H2O). The proposed catalyst is also compared with commercial Pt/C catalyst, comparable catalytic performance and better stability are obtained. It is expected that the ZnO/rGO hybrid could be used as promising non-precious metal cathode in alkaline fuel cells.

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33

Sasidharan, Sarika, and Rijith Sreenivasan. "Transition metal mixed oxide-embedded graphene oxide bilayers as an efficient electrocatalyst for optimizing hydrogen evolution reaction in alkaline media." New Journal of Chemistry 44, no. 32 (2020): 13889–901. http://dx.doi.org/10.1039/d0nj00581a.

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A novel electrocatalyst containing different percentages of iron-titanium mixed oxide onto graphene oxide (GO) support was prepared by embedding via the thermal decomposition method (TD) and was coated on a Cu substrate through facile electroless Ni–Co–P plating.

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34

MAZUR, Denys, Yaroslav KURYS, Vyacheslav KOSHECHKO, and Vitaly POKHODENKO. "EFFECTIVE ELECTROCATALYST FOR HYDROGEN EVOLUTION FROM WATER BASED ON VANADIUM DOPED Mo2C, Mo2N AND REDUCED GRAPHENE OXIDE." Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences 2022, no. 70 (September 30, 2022): 7–15. http://dx.doi.org/10.37827/ntsh.chem.2022.70.007.

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Molybdenum compounds (Mo2C, MoS2, MoP, Mo2N, etc.) and their composites with different nanosized carbon materials are considered to be one of the most promising Pt-free hydrogen evolution reaction (HER) electrocatalysts. Along with non-metallic dopants (N, P etc.), d-metals are also used as dopants to increase the activity of Mo-containing hybrid catalysts in HER. Thus, we have recently shown the possibility of obtaining HER nanocomposite electrocatalysts based on vanadium doped particles of Mo2C and N,P-doped reduced graphene oxide (rGO) using precursor based on polypyrrole, H3PVMo11O40 (PVMo11) and rGO – V-Mo2C/N,P-rGO. It was found that doping with vanadium atoms in situ promotes an increase in the activity of catalysts in HER, compared with the analogue obtained in the absence of V doping. The nature of the nitrogen-containing conjugated polymer can also affect the type of metal-containing particles formed during the high-temperature processing of such macromolecules together with the metal precursors. Given this, the paper shows the possibility of obtaining a promising hybrid electrocatalyst for HER based on vanadium-doped Mo2C, Mo2N and N,P-doped rGO (V-Mo2C,Mo2N/N,P-rGO) by pyrolysis of composite-precursor based on poly-5-aminoindole, PVMo11 and rGO. It was found that the simultaneous presence of Mo2C and Mo2N phases in the catalyst causes an increase in the activity of V-Mo2C,Mo2N/N,P-rGO in HER compared to the analogue containing only Mo2C phase (V-Mo2C/N,P-rGO), which is manifested in reduction in hydrogen evolution overpotential at a current density of 10 mA/cm2 (on 15-29 mV), an increase in the magnitude of exchange currents (by ~ 2.3-2.7 times), as well as in the anodic shift of the process onset potential and the reduction of Tafel slope (in alkaline electrolyte).

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35

Tang, Tao, Xijie Li, Zhanhui Feng, and Yingju Liu. "A needle-like cobalt-based bifunctional catalyst supported on carbon materials for effective overall water splitting." Nanotechnology 33, no. 6 (November 15, 2021): 065704. http://dx.doi.org/10.1088/1361-6528/ac328d.

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Abstract Nowadays, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) dual-functional electrocatalyst in the field of water electrolysis has great advantages in reducing costs and simplifying electrolytic cell installations. Herein, Co–Mo particles were electrodeposited on the carbon nanotubes (CNTs)/reduced graphene oxide (rGO)-modified copper foam to form the Co–Mo-CNTs/rGO-copper foam (CF), then it was subjected to a certain potential for alkaline etching, thus needle-like E-Co–Mo-CNTs/rGO-CF was synthesized. Results showed that the material surface mainly formed by the interlacing of Co oxide was more conducive to capturing the intermediates in the HER/OER reaction, while the CNTs/rGO-CF structure was closely connected to the metal layer, making excellent performance of total hydrolysis in KOH. The electrocatalyst exhibited remarkable electrocatalytic activity for HER and OER in 1 M KOH, requiring only 71 and 268 mV overpotential to drive 10 mA·cm−2, respectively. Especially, only a battery voltage of 1.52 V was needed to drive 10 mA·cm−2 in two-electrode system for overall water splitting. This work provides a method for the construction of dual-functional electrocatalyst that combined carbon materials and metals.

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36

Boettcher, Shannon W., Aaron James Kaufman, and Meikun Shen. "(Invited) Nanoscale Electrocatalyst/Semiconductor Interfaces As Charge-Carrier-Selective Contacts in Photocatalytic and Photoelectrochemical Systems." ECS Meeting Abstracts MA2022-01, no. 36 (July 7, 2022): 1570. http://dx.doi.org/10.1149/ma2022-01361570mtgabs.

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Charge-carrier-selective interfaces between electrocatalyst particles and semiconductor light absorbers are critical for solar photochemistry but controlling their properties is challenging. In this talk I will show that the nanoelectrode tip of an atomic-force-microscope cantilever can sense the surface electrochemical potential of thin-film and nanoscale electrocatalysts coating semiconductor photoelectrodes during operation. This technique allowed us to unambiguously show that metal (oxy)hydroxide layers act as both hole collectors and oxygen-evolution catalysts on metal-oxide photoanodes such as Fe2O3 and BiVO4. We also discovered the critical role that heterogeneous interfacial barrier heights, and a related nanoscale pinch-off effect, play in building carrier-selective interfaces in semiconductor photoelectrodes for generating fuel from sunlight. As specific example, thin films and nanoparticle of Pt hydrogen-evolution catalysts on p-InP, a high-performance photocathode material, along with macroscopic and nanoscopic electrical and chemical analysis, are used to show how hydrogen alloying, the pinch-off effect for nanoscale contacts, and the formation of a native surface oxides all play different roles in creating charge-carrier-selective junctions. The sum of these new insights can be broadly applied to photocathodes, photoanodes, and overall water-splitting systems to control charge-carrier selectivity and improve performance.

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37

Luo, Kaikai, Qilong Zheng, Yi Yu, Chunchang Wang, Shanshan Jiang, Haijuan Zhang, Yu Liu, and Youmin Guo. "Urea-Assisted Sol-Gel Synthesis of LaMnO3 Perovskite with Accelerated Catalytic Activity for Application in Zn-Air Battery." Batteries 9, no. 2 (January 29, 2023): 90. http://dx.doi.org/10.3390/batteries9020090.

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Precious metal-based materials such as commercial Pt/C are available electrocatalysts for redox reactions in Zn-air batteries. However, their commercial use is still limited by slow kinetics and restricted stability. In this work, we highlight a facial urea-assisted sol-gel method to synthesize A-site vacancy in LaMnO3+δ oxide for boosting its catalytic activity and further explore the effect of the amount of urea on the A-site LaMnO3. The A-site vacancy in LMO was confirmed by XRD, TEM, and XPS, which revealed that the urea-assisted sol-gel method mitigated the A-site vacancy in LaMnO3+δ and increased its surface area, thus ultimately accelerating its redox reaction kinetics. The half-wave potential and current density of the resultant 3.0U-LMO electrocatalyst were 0.74 V and 5.74 mA cm−2, respectively. It is worth noting that the assembled Zn-air battery with the 3.0U-LMO catalyst presented a power output of 130.04 mW cm−2 at 0.51 V and a promising energy efficiency of 58.4% after 150 cycles. This protocol might offer an efficient approach for developing new defect-regulated perovskites for electrocatalysis.

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38

Silva, Cristina, Irina Borbáth, Kristóf Zelenka, István E. Sajó, György Sáfrán, András Tompos, and Zoltán Pászti. "Effect of the reductive treatment on the state and electrocatalytic behavior of Pt in catalysts supported on Ti0.8Mo0.2O2-C composite." Reaction Kinetics, Mechanisms and Catalysis 135, no. 1 (December 11, 2021): 29–47. http://dx.doi.org/10.1007/s11144-021-02131-4.

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AbstractTi(1-x)MoxO2-carbon composites are promising new supports for Pt-based electrocatalysts in polymer electrolyte membrane fuel cells offering exciting catalytic properties and enhanced stability against electrocorrosion. Pt and the mixed oxide form a couple liable for strong metal-support interaction (SMSI) phenomenon, generally manifesting itself in decoration of the metal particles by ultrathin layers of the support material upon annealing under reductive conditions. The aim of this work is to evaluate the SMSI phenomenon as a potential strategy for tailoring the properties of the electrocatalyst. A 20 wt% Pt/50 wt% Ti0.8Mo0.2O2-50 wt% C electrocatalyst prepared on Black Pearls 2000 carbon functionalized with HNO3 and glucose was reduced at 250 °C in H2 in order to induce SMSI. The electrocatalytic properties and the stability of the reduced and the original catalysts were analyzed by cyclic voltammetry and COads stripping voltammetry. Structural investigations as well as X-ray photoelectron spectroscopy (XPS) measurements were performed in order to obtain information about the details of the interaction between the oxide and the Pt particles. The electrochemical experiments pointed out a small loss of the electrochemically active surface area of Pt in the reduced catalyst along with enhanced stability with respect to the original one, while structural studies suggested only a minimal decrease of the Pt dispersion. At the same time, hydrogen exposure experiments combined with XPS demonstrated the presence of Mo species directly adsorbed on the Pt surface. Thus, the properties of the reduced catalyst can be traced to decoration of the surface of Pt by Mo-containing species.

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39

Davari, Elaheh, and Douglas G. Ivey. "Mn-Co oxide/PEDOT as a bifunctional electrocatalyst for oxygen evolution/reduction reactions." MRS Proceedings 1777 (2015): 1–6. http://dx.doi.org/10.1557/opl.2015.449.

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ABSTRACTBifunctional electrocatalysts, which facilitate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), are vital components in advanced metal-air batteries. Results are presented for carbon-free, nanocrystalline, rod-like, Mn-Co oxide/PEDOT bifunctional electrocatalysts, prepared by template-free sequential anodic electrodeposition. Electrochemical characterization of synthesized electrocatalysts, with and without a conducting polymer (PEDOT) coating, was performed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). In addition, microstructural characterization was conducted using SEM, TEM, STEM and XPS. Mn-Co oxide/PEDOT showed improved ORR/OER performance relative to Mn-Co oxide and PEDOT. On the basis of rotating disk electrode (RDE) experiments, Mn-Co oxide/PEDOT displayed the desired 4-electron transfer oxygen reduction pathway. Comparable ORR activity and superior OER activity relative to commercial Pt/C were observed.

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40

Singh, Harish, McKenzie Marley Hines, Shatadru Chakravarty, and Manashi Nath. "Multi-Walled Carbon Nanotube Supported Manganese Selenide As Highly Active Bifunctional OER and ORR Electrocatalyst." ECS Meeting Abstracts MA2022-01, no. 34 (July 7, 2022): 1376. http://dx.doi.org/10.1149/ma2022-01341376mtgabs.

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Transition metal selenides have attracted intensive interest as cost-effective electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) because of the continuous thrust in sustainable energy conversion. In this article a Mn-based bifunctional electrocatalyst, MnSe has been identified which shows efficient OER and ORR activity in alkaline medium. The catalytic activity could be further enhanced by using multiwalled carbon nanotubes (MWCNT) asadditives which increases the charge transfer and electronic conductivity of the catalyst composite. This MnSe@MWCNT catalyst composite exhibits a very low overpotential of 210 mV at 50 mA cm-2 when deposited on Ni foam, which outperforms state-of-the-art RuO2 as well as other oxide and Mn-based electrocatalysts. Furthermore, the composite’s facile OER kinetics was evidenced by its small Tafel slope of 54.76 mV dec–1 and low charge transfer resistance, indicating quick transport of the reactant species. The MnSe@MWCNT also exhibited efficient electrocatalytic activity for ORR with a Eonset of 0.94 V, which is among the best reported till date for chalcogenide based ORR electrocatalysts. More importantly, this MnSe-based ORR electrocatalyst exhibits high degree of methanol tolerance, showing no degradation of catalyst performance in presence of copious quantities of methanol, thereby out-performing state-of-the-art Pt electrocatalyst. The catalyst compositie also exhibited exceptional functional and compositional stability for OER and ORR after prolonged period of continuous operation in alkaline medium. The surface Raman analysis after OER revealed the retention of manganese selenide surface with evidence of Mn-oxo coordination confirming the formation of mixed anionic (oxy)selenide as the active surface for OER. Such efficient bifunctional OER and ORR activity makes this MnSe based catalyst attractive for overall electrolysis in regenerative as well as direct methanol fuel cells.

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41

Boettcher, Shannon W., Aaron James Kaufman, and Meikun Shen. "(Invited) Local and Macroscopic Probes of Semiconductor/Electrocatalyst Photochemical Interfaces." ECS Meeting Abstracts MA2022-02, no. 48 (October 9, 2022): 1814. http://dx.doi.org/10.1149/ma2022-02481814mtgabs.

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Анотація:

Charge-carrier-selective interfaces between electrocatalyst particles and semiconductor light absorbers are critical for solar photochemistry but controlling their properties is challenging. In this talk I will show that the nanoelectrode tip of an atomic-force-microscope cantilever can sense the surface electrochemical potential of thin-film and nanoscale electrocatalysts coating semiconductor photoelectrodes during operation. This technique allowed us to unambiguously show that metal (oxy)hydroxide layers act as both hole collectors and oxygen-evolution catalysts on metal-oxide photoanodes such as Fe2O3 and BiVO4. We also discovered the critical role that heterogeneous interfacial barrier heights, and a related nanoscale pinch-off effect, play in building carrier-selective interfaces in semiconductor photoelectrodes for generating fuel from sunlight. As specific example, thin films and nanoparticle of Pt hydrogen-evolution catalysts on p-InP, a high-performance photocathode material, along with macroscopic and nanoscopic electrical and chemical analysis, are used to show how hydrogen alloying, the pinch-off effect for nanoscale contacts, and the formation of a native surface oxides all play different roles in creating charge-carrier-selective junctions. These measurements are compared and contrasted to a new approach to “wirelessly” measure interfacial for different contact materials by analyzing shifts in element-specific shifts in x-ray photoelectron emission energies. The sum of these new insights can be broadly applied to photocathodes, photoanodes, and overall water-splitting systems to control charge-carrier selectivity and improve performance.

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42

Haber, Joel A., Eitan Anzenburg, Junko Yano, Christian Kisielowski, and John M. Gregoire. "Multiphase Nanostructure of a Quinary Metal Oxide Electrocatalyst Reveals a New Direction for OER Electrocatalyst Design." Advanced Energy Materials 5, no. 10 (February 27, 2015): 1402307. http://dx.doi.org/10.1002/aenm.201402307.

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43

Amar, Ibrahim A., and Mohammed M. Ahwidi. "Electrocatalytic Activity of Lanthanum Chromite-Based Composite Cathode for Ammonia Synthesis from Water and Nitrogen." Advanced Materials Research 1160 (January 2021): 65–74. http://dx.doi.org/10.4028/www.scientific.net/amr.1160.65.

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Анотація:

The electrocatalytic ammonia synthesis using water (along with nitrogen) as a hydrogen source is proposed as an alternative green and clean technology to the energy-intensive and CO2-emitting process (Haber-Bosch) for ammonia production. Besides, a selective electrocatalyst for ammonia synthesis versus the competing hydrogen evolution remains elusive. This study aims to investigate the electrocatalytic activity of non-noble metal Co and Fe-free perovskite oxide-based composite cathode (La0.75Sr0.25Cr0.5Mn0.5O3-δ-Ce0.8Gd0.18Ca0.02O2-δ) towards ammonia synthesis from H2O and N2. The electrocatalyst was synthesized via a sol-gel process and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was successfully with a maximum formation rate of 2.5 × 10-10mol s-1cm-2and Faradaic efficiency of 0.52% at 400 oC and applied voltage of 1.4 V. The results demonstrated that the proposed non-noble metal-based electrocatalyst is a promising material for the carbon-free ammonia synthesis process.

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44

Williford, R. E., and L. A. Chick. "Surface diffusion and concentration polarization on oxide-supported metal electrocatalyst particles." Surface Science 547, no. 3 (December 2003): 421–37. http://dx.doi.org/10.1016/j.susc.2003.10.026.

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45

Barakat, Nasser A. M., Enas Ahmed, A. A. Farghali, Mamdouh M. Nassar, Gehan M. K. Tolba, and Ayman H. Zaki. "Facile synthesis of Ni-incorporated and nitrogen-doped reduced graphene oxide as an effective electrode material for tri(ammonium) phosphate electro-oxidation." Materials Advances 3, no. 6 (2022): 2760–71. http://dx.doi.org/10.1039/d1ma01069g.

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Анотація:

Drying well-mixed Ni(CH3COO)2-PVP solution results in incorporation of metal precursor NPs throughout the polymer sheets. Adjusting the metal salt content leads to produce N-doped and Ni-decorated rGO which is an effective electrocatalyst for H2 production from tri(ammonium) phosphate.

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46

Matsuzawa, Koichi, Yuma Kohara, Soma Hirayama, Satoshi Yamada, and Akimitsu Ishihara. "(Digital Presentation) Oxygen Evolution Reaction on Non-Precious Metal Oxide-Based Electrocatalysts With and Without Low Potential Scan in Acidic Solution." ECS Transactions 109, no. 9 (September 30, 2022): 451–61. http://dx.doi.org/10.1149/10909.0451ecst.

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In order to develop non-platinum group metals anode electrocatalyst for the proton exchange membrane water electrolysis, the catalytic activity of Mn added Ta and Mo oxide-based electrocatalyst with and without low potential scan for the oxygen evolution reaction (OER) have been investigated. Both Mn added Ta and Mo oxide-based electrocatalyst without low potential scan (Mn-TaOx (E low = 1.2 V) and Mn-MoOx (E low = 1.2 V)) had much higher OER activity than that with low potential scan ((Mn-TaOx (E low = 0.05 V) and Mn-MoOx (E low = 0.05 V)) because the charge transfer resistance of both Mn-TaOx and Mn-MoOx (E low = 1.2 V) were drastically smaller than that of Mn-TaOx and Mn-MoOx (E low = 0.05 V). From SEM and XPS spectra, containing amount of Mn has maintained after electrochemical measurement in both bulk and surface of Mn-TaOx and Mn-MoOx without low potential scan (E low = 1.2 V) while containing amount of Mn was reduced after electrochemical measurement in both bulk and surface of Mn-TaOx and Mn-MoOx with low potential scan (E low = 0.05 V).

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47

Li, Peipei, Jianwei Wang, Hongyu Chen, Xuping Sun, Jinmao You, Shanhu Liu, Youyu Zhang, Meiling Liu, Xiaobin Niu, and Yonglan Luo. "Synergistic electrocatalytic N2 reduction using a PTCA nanorod–rGO hybrid." Journal of Materials Chemistry A 7, no. 20 (2019): 12446–50. http://dx.doi.org/10.1039/c9ta03654g.

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As a non-noble-metal electrocatalyst for the N₂ reduction reaction, a perylene-3,4,9,10-tetracarboxylic acid nanorod-reduced graphene oxide hybrid offers a large NH₃ yield of 24.7 μg h⁻¹ mg_cat.⁻¹ with a high faradaic efficiency of 6.9%.

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48

Khotib, Mohammad, Bambang Soegijono, Zainal Alim Mas’ud, and Komar Sutriah. "Electrocatalytic Properties of Ni-Doped BaFe12O19 for Oxygen Evolution in Alkaline Solution." Open Chemistry 17, no. 1 (December 31, 2019): 1382–92. http://dx.doi.org/10.1515/chem-2019-0139.

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AbstractTransition metal oxide (TMO) continues to be studied and developed as an oxygen evolution reaction (OER) electrocatalyst due to its abundance and low price. The aim of this experiment was to evaluate Ni2+-doped BaFe12O19 (BHF) as an OER electrocatalyst in an alkaline medium. BHF and Ni-doped BHF was synthesized through a low temperature coprecipitation technique followed by a calcination process at 750oC for 4 h. Diffractograms of the BHF and the Ni-doped BHF indicated a single phase on the synthesized BHF and formed Fe2O3 impurities on the Ni-doped BHF. SEM images showed a homogenous plate-shaped particles in the BHF, while the Ni-doped BHF had larger inhomogeneous particles. Ni dopant increased OER electrocatalytic activity of BHF based on overpotential on specific current density. The Ni-doped BHF had comparable activity to some metallic oxides based on their overpotential values at specific current density value.

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49

Li, Changli, Yequan Xiao, Li Zhang, Yanbo Li, Jean-Jacques Delaunay, and Hongwei Zhu. "Efficient photoelectrochemical water oxidation enabled by an amorphous metal oxide-catalyzed graphene/silicon heterojunction photoanode." Sustainable Energy & Fuels 2, no. 3 (2018): 663–72. http://dx.doi.org/10.1039/c7se00504k.

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In conjunction with a TiO₂ protective layer and FeNiCoOx electrocatalyst, a graphene/Si heterojunction photoanode is demonstrated as a new type of Si-based buried junction with high photovoltage for solar water oxidation.

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50

Hanan, Abdul, Abdul Jaleel Laghari, Muhammad Yameen Solangi, Umair Aftab, Muhammad Ishaque Abro, Dianxue Cao, Mukhtiar Ahmed, et al. "CDO/CO3O4 NANOCOMPOSITE AS AN EFFICIENT ELECTROCATALYST FOR OXYGEN EVOLUTION REACTION IN ALKALINE MEDIA." International Journal of Engineering Science Technologies 6, no. 1 (January 15, 2022): 1–10. http://dx.doi.org/10.29121/ijoest.v6.i1.2022.259.

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Electrochemical water splitting is one of the promising way to enhance energy with less outflow. In this regard different electrocatalysts have been reported for Oxygen evolution reaction (OER) to get alternative of noble metal based electrocatalysts. In this work, we have introduced Cadmium-oxide/Cobalt-oxide (CdO/Co3O4) nanocomposite by co-precipitation chemical strategy with impressive OER performance in alkaline medium. Almost 310 mV overpotential value is required to achieve 10 mA/cm2 current density with Tafel slope value of 62 mV/Dec. The as synthesized nanocomposite has stability of 6h as its longer electrochemical performance

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