Tesis sobre el tema "Green hydrogen production"
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Berry, James Thomas. "Hydrogen production in the green alga Chlamydomonas reinhardtii". Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429038.
Texto completoWilliams, Charlotte R. "Pattern formation and hydrogen production in suspensions of swimming green algae". Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/1370/.
Texto completoChidziva, Stanford. "Green hydrogen production for fuel cell applications and consumption in SAIAMC research facility". University of Western Cape, 2020. http://hdl.handle.net/11394/7859.
Texto completoToday fossil fuels such as oil, coal and natural gas are providing for our ever growing energy needs. As the world’s fossil fuel reserves fast become depleted, it is vital that alternative and cleaner fuels are found. Renewable energy sources are the way of the future energy needs. A solution to the looming energy crisis can be found in the energy carrier hydrogen. Hydrogen can be produced by a number of production technologies. One hydrogen production method explored in this study is electrolysis of water.
Lang, Chengguang. "Monoatomic Metal Doped Nanomaterials for Hydrogen Production and Storage". Thesis, Griffith University, 2022. http://hdl.handle.net/10072/419714.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
Full Text
Basu, Alex. "Relation between hydrogen production and photosynthesis in the green algae Chlamydomonas reinhardtii". Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-242624.
Texto completoLi, Molly Meng-Jung. "Bimetallic alloy catalysts for green methanol production via CO2 and renewable hydrogen". Thesis, University of Oxford, 2018. https://ora.ox.ac.uk/objects/uuid:7e28950e-85e9-4d9a-b791-3f5d1172065e.
Texto completoMONTENEGRO, CAMACHO YEIDY SORANI. "Green hydrogen production from biogas autothermal reforming processor coupled with soot trap". Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2674736.
Texto completoAlex, Ansu. "Tidal stream energy integration with green hydrogen production : energy management and system optimisation". Thesis, Normandie, 2022. http://www.theses.fr/2022NORMC216.
Texto completoThe overarching aim of this thesis is to design, implement and compare different energy management strategies and optimisation approaches for a hybrid system involving floating tidal stream energy integration with green hydrogen production. Towards reaching the objectives, the individual system components are modelled initially. The annual system performance capabilities of the tidal stream energy plant are then obtained using frequently occurring daily profiles at the Fall of Warness berth in the Orkney Islands, Scotland. The transitionary operating modes of two polymer electrolyte membrane electrolyser units, when subjected to the energy from the tidal stream plant are analysed based on a rule-based approach energy management strategy. Later, a preliminary evaluation of the hydrogen production cost is assessed based on different daily hydrogen demand and daily tidal profile conditions. Further, an optimisation approach with the objective to maximise the system operating profit ensuring optimal and sufficient operations of both the electrolyser units under real system constraints, is formulated with priority for tidal energy powered hydrogen production. The optimisation problem is solved using a genetic algorithm based on the mixed integer non-linear problem. A comprehensive cost-benefit analysis based on fixed-variable costs and levelised costs factors is performed to analyse the optimal techno-enviro-economic operation of a hybrid grid connected tidal-wind-hydrogen energy system. The outcomes are compared against the rule-based approach results. The annualised profits in the optimisation approach are estimated to be 41.5% higher compared to the rule-based approach. Further, from an environmental view, the best optimisation results are approximately 47% higher than the rule-based approach results in terms of carbon emission reductions. A dynamic electrolyser capable of working at twice of its nominal power rating for limited duration, resulted particularly advantageous when coupled with tidal energy which is cyclic in nature with predictable periods of high and low power generation. Finally, it was determined that the fixed cost (FC) optimisation approach is relatively simple in terms of cost estimation. On the contrary, while the levelised cost (LC) approach yields slightly better results, it necessitates a greater prior knowledge of system operations to reasonably estimate the cost factors. The proposed method can be used as a generic tool for electrolytic hydrogen production analysis under different contexts, with preferable application in high green energy potential sites with constrained grid facilities
Scoma, Alberto <1980>. "Physiology and Biotechnology of the Hydrogen Production with the Green Microalga Chlamydomonas reinhardtii". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2321/1/Scoma_Alberto_Thesis.pdf.
Texto completoScoma, Alberto <1980>. "Physiology and Biotechnology of the Hydrogen Production with the Green Microalga Chlamydomonas reinhardtii". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2321/.
Texto completoRossi, Gianmarco. "modeling of proton exchange membrane water electrolyzer for green hydrogen production from solar energy". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Buscar texto completoÖHMAN, AXEL. "Green hydrogen production at Igelsta CHP plant : A techno-economic assessment conducted at Söderenergi AB". Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299434.
Texto completoEnergiomställningen som äger rum i olika delar av världen kommer att ha många effekter på de nuvarande energisystemen eftersom en ökande mängd väderberoende kraftproduktion installeras varje år. I Sverige, precis som många andra länder, kommer detta att medföra både utmaningar och möjligheter för dagens energiproducenter. Utmaningar som kan uppstå tillsammans med en alltmer fluktuerande elproduktion inkluderar både kraftunderskott vid vissa tider och regioner men också timmar av överproduktion som kan få elpriserna att sjunka avsevärt. Sådana utmaningar måste mötas av både planerbar kraftproduktion och dynamisk konsumtion. Omvänt kan aktörer som är beredda att anpassa sig till det nya klimatet genom att implementera ny teknik eller innovativa affärsmodeller dra nytta av övergången till ett helt förnybart energisystem. Denna rapport utvärderar den tekno-ekonomiska potentialen för produktion av grön vätgas vid ett kraftvärmeverk med målet att ge beslutsstöd till en fjärrvärme- och elproducent i Sverige. Det var i företagets intresse att undersöka hur vätgasproduktion kan bidra till att sänka produktionskostnaden för fjärrvärme samt bidra till att minska växthusgaser. I projektet utvärderades två separata affärsmodeller: Power-to-gas och Power-to-power baserat på teknisk och ekonomisk prestanda samt miljöpåverkan. För att kunna göra detta utvecklades en matematisk modell i Python av kraftvärmeverket och vätgassystemen som optimerar driften baserat på kostnader. Affärsmodellerna simulerades sedan för två olika års elpriser för att undersöka modellens prestanda i olika typer av elmarknader. De viktigaste slutsatserna i studien visar att Power-to-gas redan kan vara lönsamt till ett vätgaspris på 40 SEK per kg, vilket är det förväntade marknadspriset på grön vätgas for transportsektorn. Efterfrågan är idag begränsad men förväntas växa snabbt inom en snar framtid, särskilt inom tung transport. En annan begränsande faktor för vätgasproduktion visade sig vara tillgången på lagringsutrymme, eftersom vätgas även vid tryck upp till 200 bar kräver stora volymer. Power-to-power för frekvensreglering visade sig inte vara ekonomiskt försvarbart, eftersom intäkterna för att tillhandahålla nättjänster inte kunde uppväga de höga investeringskostnaderna under några av de simulerade åren. Detta resulterade i en hög LCOE på över 3000 SEK per MWh, vilket främst berodde på Power-to-power-systemets låga utnyttjandegrad. Slutligen kan det sägas att grön vätgas har stor potential att ersätta fossila bränslen i sektorer som är svåra att elektrifiera, exempelvis tunga vägtransporter eller sjöfart. Därför kan storskalig grön vätgasproduktion hjälpa till att dekarbonisera många av samhällets fossiltunga segment. Genom att dessutom fungera som balansering har väteproduktion i en Power-to-gas-process potential att bli en viktig del av ett system med stor andel förnybar energi.
Johnson, Daniel. "Investigation of the Physiology of Hydrogen Production in the Green Alga Chlamydomonas reinhardtii Using Spectral-Selective Photosystem I Light". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311581.
Texto completoHoshino, Takanori. "Design of Novel Strategy for Green Algal Photo-Hydrogen Production: Spectral-Selective Photosystem I Activation and Photosystem II Deactivation". Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/196095.
Texto completoSood, Sumit. "Multiphysics modelling for online diagnosis and efficiency tracking : application to green H2 production". Thesis, Université de Lille (2018-2021), 2021. https://pepite-depot.univ-lille.fr/LIBRE/EDMADIS/2021/2021LILUB028.pdf.
Texto completoRenewable Energy Sources (RES) have emerged as a sustainable alternative to carbon-based energy sources as the world is struggling in limiting the greenhouse effect in the coming years. The use of RES, such as solar and wind, alone is non-reliable due to their intermittent nature. The surplus electricity generated during off-peak hours must be stored to tackle the problem of the unavailability of energy. Green Hydrogen (GH$_2$) generation using electrolyser running on RES has seen an increase in recent years for the storage of this surplus energy due to its advantages over conventional methods (such as batteries and ultra-capacitors) for long term storage and transport. Proton Exchange Membrane (PEM) based electrolysers are better suited for the coupling with RES as compared to the alkaline electrolysers due to their faster start-up times and fast dynamic load changing capability. The intermittent nature of RES affects the performance and operation dynamics of the PEM electrolyser and must be analysed and studied in order to make these systems more reliable and safer to use. Mathematical modelling is one of the possible solutions for studying their behavior and developing supervision algorithms.Under the framework of the E2C project of the European Interreg 2-Seas program, a generic dynamic multi-physics model of a PEM electrolyser has been proposed in this work based on Bond Graph (BG) approach. Various components of the PEM electrolyser have been modelled in the form of BG capsules. These capsules can be connected based on the piping and instrumentation diagram of the PEM electrolyser system to have a global model of the system. The developed model is capable of representing different configurations of PEM electrolysers ranging from laboratory scale to industrial scale. The model is also capable of facilitating efficiency tracking in real-time. The developed model in the BG form has been converted into MATLAB® Simulink block diagram from the implementation point of view.The model was then validated using a single cell PEM electrolyser powered by a Hybrid Multi-source Platform (HMP) running on solar and wind energy at the University of Lille. The proposed model was also extended for the modelling and performance study of Anion Exchange Membrane (AEM) electrolysis cell, in collaboration with the University of Exeter of England, which shares a similar configuration and architecture.The developed model for the PEM electrolysis system is also suitable for the development of control, diagnosis, and prognosis algorithms. Therefore, a model-based robust fault diagnosis for PEM water electrolyser has been proposed in this work. The proposed diagnosis algorithms and model have been then utilized for developing the graphical user interface for online supervision
VASUDEVAN, ROHAN ADITHYA. "SWOT-PESTEL Study of Constraints to Decarbonization of the Natural Gas System in the EU Techno-economic analysis of hydrogen production in Portugal : Techno-economic analysis of hydrogen production in Portugal". Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-292186.
Texto completoDet starka behovet av att ta itu med klimatförändringarna och deras negativa effekter är omfattande världen över. Den europeiska unionen utgör en pionjär när det gäller att såväl hantera sina koldioxidberoende och utsläpp som att implementera reglerande miljöpolitik, och framstår därmed som överlägsen andra stater och organisationer i detta hänseende. Unionen är emellertid fortfarande mycket beroende av fossilt bränsle för att uppfylla sina energibehov, och kvarstår därför som en av världens största importörer av naturgas. Syftet med denna forskningsavhandling är att undersöka befintliga hinder och restriktioner i EU: s politiska ramverk som medför konsekvenser avkolningen av naturgas, samt att undersöka de utjämnande kostnaderna för väteproduktion (LCOH) som kan användas för att avkolna naturgassektorn. Därmed utförs en omfattande studie baserad på befintlig akademisk och vetenskaplig litteratur, EU: s politiska ramverk och stadgar som är relevanta för naturgasindustrin. Dessutom genomförs en teknisk-ekonomisk analys av eventuella ersättningar av naturgas med väte. Valet av väte som forskningsobjekt motiveras olika forskningsstudier som indikerar vikten och förmågan att ersätta till naturgas. Till sist berör studien Portugal. som tillhandahåller en lämplig miljö för billig och grön vätgasproduktion. Av denna anledning är Portugal utvalt som den viktigaste utvärderingsregionen. Studien utvärderar det nuvarande ramverket baserat på en SWOT-analys ((Strength, Weakness, and Opportunities & Weakness), som inkluderar en PESTEL (Political, Economical, Social, Technological, Environmental och Legal) makroekonomisk faktoranalys och elicitering. Den utjömnade vätekostnaden beräknades i blått (SMR - Ångmetanreformering med naturgas som råvara) och grönt väte (elektrolyser med el från elnät, sol och vindkällor). Kostnaderna var specifika för de portugisiska förhållandena under åren 2020, 2030 och 2050 baserat på tillgänglighet av data samt anpassningen till den nationella energi- och klimatplanen (NECP) och klimatåtgärdsramen 2050. Storleken på elektrolyserar baseras på den nuvarande marknadskapaciteten medan SMR är begränsad till 300 MW. Avhandlingen tar endast hänsyn till produktionen av vätgas. Transmission, distribution och lagring av väte ligger utanför analysens räckvidd. Resultaten visar att hindren är främst relaterade till kostnadskonkurrens, förändringar i stadgar och bestämmelser, incitament och begränsningar i formerandet av efterfrågan på koldioxidsnåla gaser på marknaden. Att säkerställa energiförsörjning och tillgång på ett ekonomiskt hållbart sätt kräver omedelbara ändringar av reglerna och politiken, såsom att stimulera utbudet, att skapa en efterfrågan på koldioxidsnåla gaser och genom att beskatta kol. När det gäller LCOH dominerar blåväte beträffande produktionskostnaderna (1,33 € per kg H2) jämfört med grönt väte (4,27 respektive 3,68 € per kg H2) från elnät respektive solenergi. Osäkerhetsanalysen visar vikten av investeringskostnader och effektiviteten vid elektrolysörer och koldioxidskatten för SMR. Med förbättringar av elektrolys-tekniken och ökad koldioxidskatt skulle upptagningen av grön vätgas vara enklare och säkerställa en rättvis men konkurrenskraftig gasmarknad.
THANH, HUYNH TAN y HUYNH TAN THANH. "PdxNiy Bimetallic Nanocatalysts for Green Production of Hydrogen Peroxide". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/768jd8.
Texto completo國立臺灣科技大學
化學工程系
103
It is well-known that hydrogen peroxide is a highly versatile environmentally friendly industrial oxidant. Recently, palladium and bimetallic palladium gold catalysts have come to prominence, due to their high selectivity and activity. However, the high cost of gold both limits their wide application in industry and at the same time fuels research into alternative catalytic metals able to replace gold in bimetallic catalysts. This study focuses on PdxNiy bimetallic nanocatalysts for green production of hydrogen peroxide. In this work a new supported catalyst for the direct synthesis of hydrogen peroxide was developed. Nickel has been adopted as the catalytic candidate due to its low cost compared to gold. Two main approaches were taken to synthesize PdxNiy nanocatalysts. NaBH4 and H2 were applied as a reductive agent to reduce Pd2+ and Ni2+ in precursors to form bimetallic PdxNiy on pretreated-carbon, respectively. However, the analysis results show that NaBH4 was not able to reduce Ni2+, and the H2 reduction method cannot achieve desired interaction between nanocatalysts and support. Thus, mesoporous carbon support and the organic agent reduction method were further developed for the synthesis of bimetallic nanocatalysts which were characterized by the crystallographic face-centered-cubic structure. Next, it is demonstrated that the alloy crystal structure of PdxNiy alloy can be arranged into the face-centered tetragonal (fct) structure after hydrogen treatment. Attributed to the ordered structure, the fct- PdxNiy catalyst found in this study enhances not only structural stability but also productivity with respect to the direct synthesis of hydrogen peroxide.
Hasiholan, Bonavian y Bonavian Hasiholan. "Bimetallic Nanocatalysts Based Green Process for Production of Hydrogen Peroxide". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/74631131340516106837.
Texto completo國立臺灣科技大學
化學工程系
99
The purpose of this study is to develop a new green process for production of H2O2 through the direct synthesis route, of which the hydrogen and oxygen contacts each other during the reaction. An electrochemical approach with the rotating ring disk electrode (RRDE) had been systematically explored and developed accordingly to measure the produced H2O2. Two different methods – co-reduction and successive reduction prepared in the microwave were adopted to prepare bimetallic Pd-Au/C nanocatalysts. The relationship between the structure of prepared nanocatalysts and their catalytic activity in the direct synthesis process were investigated. As synthesized bimetallic Pd-Au/C were characterized by ICP-AES, XRD, SEM, TEM, and XAS for better understanding in the catalytic activity of direct synthesis of H2O2. The approach in the electrochemical to measure H2O2 produced from direct synthesis has been successfully done with the detection method 2, where the catalyst is dispersed homogenously in the solution. The calibration curve of the different concentration of H2O2 is made in the parameter of 0.891 V (vs Ag/AgCl) and with the scan rate 50 mV/s. The optimum loading of samples prepared by co reduction was observed in CR Pd3%-Au2%/C with the productivity of H2O2 is 65.8 mol.kgcat-1h-1. This productivity is higher than the other prepared catalysts, such as monometallic Pd0%-Au5% & Pd5%-Au0% and bimetallic SR Pd-Au/C that is prepared by successive reduction. The higher or the lower productivity of one sample to another was explained by the parameter of the particle size, the structure of the bimetallic Pd-Au/C, the selective crystalline plane, and the role of palladium and gold. The smaller the particle size tends to Pd rich, while the larger one tends to Au rich. The smaller particle size yielded in the high surface area, thus the productivity increases. However, if the particle size is too small, the active site or selective crystalline plane may be slightly appeared (as can be seen in SR Pd-Au/C), thus the productivity decreases. From XAS analysis, the structure CR Pd-Au/C is Au rich in core and Pd rich in shell. The structure of SR PdAu at some part of catalyst is Au rich in core and Pd rich in shell, while at the other part, the structure is Pd in core and Au in shell. The Q value of SR PdAu (0.638) is higher than that of CR PdAu (0.605), which indicates that the existence of Au atoms in the shell of SR PdAu is more than that of CR PdAu. The difference in their structure is one reason why the H2O2 productivity of CR PdAu is higher than SR PdAu. The role of Pd is to provide the surface area for the selective oxidation of hydrogen and the role of Au is to provide inactive site for the reaction of decomposition and hydrogenation of H2O2.
Hoa, Le Ngoc Quynh y 黎玉瓊花. "Reduced Graphene Oxide supported bimetallic Pd-Au nanocatalysts for green production of Hydrogen Peroxide". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/13513898968508531019.
Texto completo國立臺灣科技大學
化學工程系
102
Hydrogen Peroxide is a valuable chemical with wide spread uses in industry; its demand is recently increasing due to its utilization. The modified reduced graphene oxide supported PdAu nanocatalysts were prepared for direct synthesis of hydrogen peroxide at ambient conditions in this work. The various atomic ratios of PdAu nanocatalysts on reduced graphene oxides were synthesized and characterized by XRD, SEM, TEM, Raman, FTIR and electrochemical analysis. It is found that the Pd07Au03 nanocatalyst shows the highest productivity of hydrogen peroxide due to its higher alloying extent. The graphene oxides were further modified by sulfonation. The results indicate the productivity can be further improved when Pd07Au03 nanocatalysts were prepared on the modified reduced graphene oxide. The high productivity of hydrogen peroxide was successfully achieved on the developed PdAu/mrGO nanocatalysts at ambient conditions. The method developed for preparation of PdAu nanocatalysts on modified reduced graphene oxide opens a new and interesting direction for increasing productivity hydrogen peroxide.
Liu, Chih-Chen y 劉智禎. "Green Synthesized Silver Coated on Titanium Nanotube Arrays for Simutaneous Ibuprofen Degradation and Hydrogen Production". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/23kw72.
Texto completo東海大學
環境科學與工程學系
105
The silver nanoparticles were successfully doped on a titanium dioxide nanotube arrays (TNAs) by green synthesis. Tea and coffee extract were used as reducing agent in green synthesis, and the synthesized photocatalysts were denoted as Ag/ TNAs-t and Ag/TNAs-c, respectively. The synthesized Ag/TNAs were used as electrodes in photoelectrochemical (PEC) systems to degrade ibuprofen and produce hydrogen in the anode and cathode, respectively. Ag/TNAs-t and Ag/TNAs-c showed that silver nanoparticles were successfully deposited on titanium dioxide nanotube arrays with a diameter of about 10 nm observed by scanning electron microscope (SEM). The results of XPS showed that the amount of silver contained in Ag/TNAs-t and Ag/TNAs-c were 1.7% and 1.6%, respectively. Similar results were obtained with EDX, confirming that silver nanoparticles were successfully deposited on the surface of TNAs. The bandgap energy of Ag/TNAs-t and Ag/TNAs-c decreased from 3.2 eV to 2.7-2.8 eV after doping silver nanoparticles. In the photoelectric current measurement, Ag/TNAs-t and Ag/TNAs-c showed the photogenerated current of 2.29 and 2.50 mA/ cm2, respectively, which was 1.45 mA /cm2 higher than that of TNAs. The degradation rates of Ag/TNAs-t by electrochemical (EC), light (P), photocatalysis (PC) and photoelectrochemical (PEC) were 0.004 min-1, 0.0148 min-1, 0.0950 min-1, and 0.2132 min-1, respectively. On the other hand, the degradation rates of Ag/TNAs-c were 0.0022 min-1, 0.0639 min-1, 0.0937 min-1 and 0.2180 min-1, respectively. The results showed that the highest degradation performance were achieved in photoelectrochemical system.
Shodiya, Titilayo. "Utilization of Nano-Catalysts for Green Electric Power Generation". Diss., 2015. http://hdl.handle.net/10161/9817.
Texto completoNano-structures were investigated for the advancement of energy conversion technology because of their enhanced catalytic, thermal, and physiochemical interfacial properties and increased solar absorption. Hydrogen is a widely investigated and proven fuel and energy carrier for promising "green" technologies such as fuel cells. Difficulties involving storage, transport, and availability remain challenges that inhibit the widespread use of hydrogen fuel. For these reasons, in-situ hydrogen production has been at the forefront of research in the renewable and sustainable energy field. A common approach for hydrogen generation is the reforming of alcoholic and hydrocarbon fuels from fossil and renewable sources to a hydrogen-rich gas mixture.
Unfortunately, an intrinsic byproduct of any fuel reforming reaction is toxic and highly reactive CO, which has to be removed before the hydrogen gas can be used in fuel cells or delicate chemical processes. In this work, Au/alpha-Fe2O3 catalyst was synthesized using a modified co-precipitation method to generate an inverse catalyst model. The effects of introducing CO2 and H2O during preferential oxidation (PROX) of CO were investigated. For realistic conditions of (bio-)fuel reforming, 24% CO2 and 10% water the highest document conversion, 99.85% was achieved. The mechanism for PROX is not known definitively, however, current literature believes the gold particle size is the key. In contrast, we emphasize the tremendous role of the support particle size. A particle size study was performed to have in depth analysis of the catalysts morphology during synthesis. With this study we were also able to modify how the catalyst was made to further reduce the particle size of the support material leading to ~99.9% conversion. We also showed that the resulting PROX output gas could power a PEM fuel cell with only a 4% drop in power without poisoning the membrane electrode assembly.
The second major aim of this study is to develop an energy-efficient technology that fuses photothermal catalysis and plasmonic phenomena. Although current literature has claimed that the coupling of these technologies is impossible, here we demonstrate the fabrication of reaction cells for plasmon-induced photo-catalytic hydrogen production. The localized nature of the plasmon resonance allows the entire system to remain at ambient temperatures while a high-temperature methanol reformation reaction occurs at the plasmonic sites. Employing a nanostructured plasmonic substrate, we have successfully achieved sufficient thermal excitement (via localized surface plasmon resonance (LSPR)) to facilitate a heterogeneous chemical reaction. The experimental tests demonstrate that hydrogen gas can indeed be generated in a cold reactor, which has never been done before. Additionally, the proposed method has the highest solar absorption out of several variations and significantly reduces the cost, while increasing the efficiency of solar fuels.
Dissertation
Gultom, Noto Susanto y 孔寧天. "Development of Semiconducting Zinc Oxysulfide-Based Nano-Photocatalysts for Green, Sustainable, and High Efficient Hydrogen Production and Chemical Conversion". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/r8wfre.
Texto completo國立臺灣科技大學
材料科學與工程系
107
Energy and environmental issues have been the most concern of the worldwide in this recent decade. Due to extremely utilization of fossil energy have been causing the environmental issues like global warming and energy crisis. In the near future, the global energy needs must be obtained from the renewable and sustainable resources. Hydrogen is as a great candidate fuel to replace fossil fuels in the future since it has high energy density, zero-emission, and renewability. Unfortunately, the major hydrogen production still obtained from fossil by using steam reforming and gasification techniques. These techniques not only use unrenewable resource but also emit the carbon dioxide as the waste product. Therefore, in this particular research the green and sustainable hydrogen production is performed using photocatalytic method. This research also provides green chemical conversion of 4-nitrophenol to 4-aminophenol without using any sacrificial reagents. The first chapter of this dissertation briefly gives the introduction including background of study, hydrogen production techniques and 4-nitrophenol reduction. Then, the next chapter provides the basic theory and clear literature review of present progress in this particular research topic. This dissertation includes four works as follows. In the first work, we apply the doping concept to enhance the hydrogen production rate of Zn(O,S) with nickel as a dopant. High efficient hydrogen evolved Ni-doped Zn(O,S) photocatalyst with different Ni amounts had been successfully synthesized with a simple method at low temperature of 90C. Our Ni-doped Zn(O,S) catalyst reached the highest hydrogen generation rate of 14,800 µmole g-1·h-1, which was 2.3 times higher compared to the TiO2/Pt used as a control in this work. It was found that a small amount of Ni doped into Zn(O,S) nanoparticles could increase the optical absorbance, lower the charge transfer resistance, accordingly decrease the electron-hole recombination rate, and significantly enhance the photocatalytic hydrogen evolution reaction (HER). The as-prepared catalyst has the characteristics of low cost, low power consumption for activating the catalytic HER, abundant and environmental friendly constituents, and low surface oxygen bonding for forming oxygen vacancies. The photocatalytic performance of Ni-doped Zn(O,S) was demonstrated with a proposed kinetic mechanism in this work. In the second work, we design surface modification of Zn(O,S) by coating thin layers of graphene oxide (GO). This work demonstrates a feasible synthesis method of Zn(O,S)/GO nanocomposite with graphene oxide (GO) to serve as an inexpensive cocatalyst. Raman spectra and transmission electron microscopy (TEM) images clearly verified that GO was successfully loaded on the surface of Zn(O,S). This GO layer could effectively decrease the charge transfer resistance and promote the charge carrier separation for enhancing hydrogen production rate. By optimizing the GO content, the best hydrogen production rate of 6,400 µmol/g·h was achieved under 16W 352 nm UV lamp with Zn(O,S)/0.5 wt% GO catalyst, which showed about two times higher than GO-free Zn(O,S). The effect of sacrificial reagent on the hydrogen production rate of Zn(O,S)/0.5 wt% GO catalyst was also evaluated. The sacrificial reagent showed the efficiency with the following trend: ethanol > methanol > isopropanol > ethylene glycol. We consider the simple synthesis method of Zn(O,S)/GO and its low cost have a great potential for practical application. In the third work, the p-type Ag2O and n-type Zn(O,S) were loaded on mesoporous silica to form SiO2/Ag2O/Zn(O,S) with the nano p-n heterojunction to improve the efficiency of photocatalytic hydrogen evolution reaction (HER). The photocatalysts were systematically characterized to identify their properties. Through the optimization of the Zn(O,S)-loaded amount and position of p-Ag2O, the highest hydrogen production rate of 9,200 µmol. g-1cat.h-1 was achieved by SiO2/Ag2O/Zn(O,S)-0.6 catalyst, which was about 2.7 times higher than pure Zn(O,S). By placing n-Zn(O,S) of diodes outwards was proposed for the electron-rich part to enhance the reduction reaction, while placing p-Ag2O inwards for the hole-rich part to modulate the electron concentration and establish the built-in electrical nano field. Our design reveals that p-n heterojunction was superior and efficient for enhancing its properties and generating hydrogen. In the fourth work, the conversion of 4-nitrophenol as toxic pollutant and hazardous waste to be 4-aminophenol as non-toxic and useful compound by photocatalytic reduction was conducted. The solid solution and doping concept was combined to synthesis earth- abundant and green material Mn-doped Zn(O,S) by a simple and facile method. Different Mn contents doped Zn(O,S) was easily synthesized at low temperature of 90C for 4-NP reduction without using the reducing agent NaBH4. The Mn-doped Zn(O,S) catalyst exhibited the enhancement optical and electrochemical properties of un-doped Zn(O,S). It was found that 10% Mn doped Zn(O,S) had the best properties and it could totally reduce 4-NP after 2h photoreaction under low UV illumination. The hydrogen ion was proposed for reduction 4-NP to involved for the 4-NP reduction to 4-AP which is the hydrogen ion and electron replaced the oxygen in amino group to form the nitro group. We proposed the incorporation of Mn in Zn side in the Zn(O,S) host lattice could make the oxygen surface bonding weak to easily form the oxygen vacancy. As more oxygen vacancy, more hydrogen ion would be generated to consume for 4-NP reduction.
Langels, Hanna y Oskar Syrjä. "Hydrogen Production and Storage Optimization based on Technical and Financial Conditions : A study of hydrogen strategies focusing on demand and integration of wind power". Thesis, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-435176.
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