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Journal articles on the topic 'Inverse model catalysts'

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Author: Grafiati

Published: 10 December 2022

Last updated: 29 January 2023

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1

van Heerden, Tracey, and Eric van Steen. "Metal–support interaction on cobalt based FT catalysts – a DFT study of model inverse catalysts." Faraday Discussions 197 (2017): 87–99. http://dx.doi.org/10.1039/c6fd00201c.

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It is challenging to isolate the effect of metal–support interactions on catalyst reaction performance. In order to overcome this problem, inverse catalysts can be prepared in the laboratory and characterized and tested at relevant conditions. Inverse catalysts are catalysts where the precursor to the catalytically active phase is bonded to a support-like ligand. We can then view the metal–support interaction as a ligand interaction with the support acting as a supra-molecular ligand. Importantly, laboratory studies have shown that these ligands are still present after reduction of the catalyst. By varying the quantity of these ligands present on the surface, insight into the positive effect SMSI have during a reaction is gained. Here, we present a theoretical study of mono-dentate alumina support based ligands, adsorbed on cobalt surfaces. We find that the presence of the ligand may significantly affect the morphology of a cobalt crystallite. With Fischer–Tropsch synthesis in mind, the CO dissociation is used as a probe reaction, with the ligand assisting the dissociation, making it feasible to dissociate CO on the dense fcc Co(111) surface. The nature of the interaction between the ligand and the probe molecule is characterized, showing that the support-like ligands’ metal centre is directly interacting with the probe molecule.

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2

Tovt, Andrii, Vitalii Stetsovych, Filip Dvořák, Viktor Johánek, and Josef Mysliveček. "Ordered phases of reduced ceria as inverse model catalysts." Applied Surface Science 465 (January 2019): 557–63. http://dx.doi.org/10.1016/j.apsusc.2018.09.068.

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3

Yan, Ting, Daniel W. Redman, Wen-Yueh Yu, David W. Flaherty, José A. Rodriguez, and C. Buddie Mullins. "CO oxidation on inverse Fe2O3/Au(111) model catalysts." Journal of Catalysis 294 (October 2012): 216–22. http://dx.doi.org/10.1016/j.jcat.2012.07.024.

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4

Betti, Carolina P., Juan M. Badano, Ivana L. Rivas, Vanina A. Mazzieri, M. Juliana Maccarrone, Fernando Coloma-Pascual, Carlos R. Vera, and Mónica E. Quiroga. "Sulfur Resistance of Pt-W Catalysts." Journal of Chemistry 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/502014.

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The sulfur resistance of low-loaded monometallic Pt catalysts and bimetallic Pt-W catalysts during the partial selective hydrogenation of styrene, a model compound of Pygas streams, was studied. The effect of metal impregnation sequence on the activity and selectivity was also evaluated. Catalysts were characterized by ICP, TPR, XRD, and XPS techniques. Catalytic tests with sulfur-free and sulfur-doped feeds were performed. All catalysts showed high selectivities (>98%) to ethylbenzene. Activity differences between the catalysts were mainly attributed to electronic effects due to the presence of different electron-rich species of Pt0and electron-deficient species ofPtδ+. Pt0promotes the cleavage of H2whilePtδ+the adsorption of styrene. The catalyst successively impregnated with W and Pt (WPt/Al) was more active and sulfur resistant than the catalyst prepared with an inverse impregnation order (PtW/Al). The higher poison resistance of WPt/Al was attributed to both steric and electronic effects.

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Rosário, Roberta Lopes do, Ronaldo Costa Santos, Alan Silva dos Santos, Alexandre Carvalho, Sylvette Brunet, and Luiz Antônio Magalhães Pontes. "Niobium oxide (Nb2O5) as support for CoMo and NiW catalysts in the hydrodesulfurization reaction of 3-methylthiophene." Research, Society and Development 9, no. 11 (December 2, 2020): e74391110307. http://dx.doi.org/10.33448/rsd-v9i11.10307.

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The efficiency of niobium oxide as catalytic support of hydrodesulfurization (HDS) catalysts (CoMo and NiW) has been investigated in the HDS of a model molecule representative of sulfur compounds present in FCC gasoline (3-methylthiophene: 3MT). The NiW catalyst presented higher catalytic activity than CoMo calcined and non-calcined catalyst, however a better ratio pentane/pentene has been achieved by CoMo catalysts, which implies a lower formation of hydrogenated products. Indeed, the activity order for the catalysts evaluated is: NiW/Nb2O5 > CoMo/Nb2O5 calcined support > CoMo/Nb2O5 non-calcined support, despite the ratio pentane/pentene which has the inverse order. Furthermore, textural and chemical characterization techniques have been performed. From NH3-TPD analysis it was observed an acidity profile with a predominance of weak/strong and weak/moderate acid for CoMo and NiW catalysts, respectively. Meanwhile, the BET analysis has shown a low specific surface area for the catalysts supported by niobium oxide. Concerning the structure characteristic, the XRD analysis has suggested an amorphous phase in all catalysts analyzed.

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6

Ding, Liangbing, Feng Xiong, Yuekang Jin, Zhengming Wang, Guanghui Sun, and Weixin Huang. "Surface reaction network of CO oxidation on CeO2/Au(110) inverse model catalysts." Physical Chemistry Chemical Physics 18, no. 47 (2016): 32551–59. http://dx.doi.org/10.1039/c6cp05951a.

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7

Shi, Rui, Mausumi Mahapatra, Jindong Kang, Ivan Orozco, Sanjaya D. Senanayake, and José A. Rodriguez. "Preparation and Structural Characterization of ZrO2/CuOx/Cu(111) Inverse Model Catalysts." Journal of Physical Chemistry C 124, no. 19 (April 17, 2020): 10502–8. http://dx.doi.org/10.1021/acs.jpcc.0c00852.

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8

Bugyi, László, Imre Szenti, and Zoltán Kónya. "Promotion and inhibition effects of TiOx species on Rh inverse model catalysts." Applied Surface Science 313 (September 2014): 432–39. http://dx.doi.org/10.1016/j.apsusc.2014.05.227.

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9

Ismagilova, A. S., Z. A. Khamidullina, and S. I. Spivak. "Development and automation of algorithm for determining basis of nonlinear parameter functions of kinetic constants." Kataliz v promyshlennosti 19, no. 4 (July 11, 2019): 252–57. http://dx.doi.org/10.18412/1816-0387-2019-4-252-257.

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Mathematical modeling of catalytic processes is necessary for the complete and accurate description, as well as for controlling the quality and physicochemical studied of catalysts. In the paper, theoretical issues of industrial catalysis are discussed. The work is devoted to theoretical graph analysis of informativity of kinetic parameters of the model of a complex chemical reaction. The aim is the development and automation of algorithm for determining basis of nonlinear parameter functions in solving inverse problems of chemical kinetics in order to define the number and form of independent combinations of rate constants of elementary stages. A program package for analysis of informativity of kinetic parameters of the mathematical model of a complex catalytic reaction is developed and described. The obtained functional relations between the kinetic parameters can be useful for experimentalists in physicochemical interpretation and analysis of mechanisms of chemical reactions. In other words, the proposed method allows independent combinations of kinetic constants to be distinguished that results in shortening the number of the model parameters and, as a consequence, enhance the accuracy of the mathematical model. The mechanism of hydrogen oxidation over a platinum catalyst is given as an example of the use of the software.

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10

Lackner, Peter, Joong Il Jake Choi, Ulrike Diebold, and Michael Schmid. "Substoichiometric ultrathin zirconia films cause strong metal–support interaction." Journal of Materials Chemistry A 7, no. 43 (2019): 24837–46. http://dx.doi.org/10.1039/c9ta08438j.

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ZrO₂/metal inverse model catalysts exhibit the strong metal–support interaction (SMSI) effect. Upon annealing under reducing conditions, an oxygen-deficient_, ultrathin ZrO_≈1.5 film covers the metal. Nevertheless, Zr retains its 4+ charge state.

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11

Zhang, Jing, and J. Will Medlin. "Catalyst design using an inverse strategy: From mechanistic studies on inverted model catalysts to applications of oxide-coated metal nanoparticles." Surface Science Reports 73, no. 4 (August 2018): 117–52. http://dx.doi.org/10.1016/j.surfrep.2018.06.002.

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12

Petersen, Anna P., Roy P. Forbes, Sandeeran Govender, Patricia J. Kooyman, and Eric van Steen. "Effect of Alumina Modification on the Reducibility of Co3O4 Crystallites Studied on Inverse-Model Catalysts." Catalysis Letters 148, no. 4 (February 22, 2018): 1215–27. http://dx.doi.org/10.1007/s10562-018-2332-5.

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13

Hakkel, Orsolya, Zoltán Pászti, Tamás Keszthelyi, Krisztina Frey, and László Guczi. "Study of FeOx/Au inverse model catalysts by in situ sum frequency generation vibrational spectroscopy." Reaction Kinetics and Catalysis Letters 96, no. 2 (April 2009): 345–56. http://dx.doi.org/10.1007/s11144-009-5523-7.

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14

Xu, Lingshun, Zongfang Wu, Yuekang Jin, Yunsheng Ma, and Weixin Huang. "Reaction mechanism of WGS and PROX reactions catalyzed by Pt/oxide catalysts revealed by an FeO(111)/Pt(111) inverse model catalyst." Physical Chemistry Chemical Physics 15, no. 29 (2013): 12068. http://dx.doi.org/10.1039/c3cp50292a.

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15

Chen, Haoran, Wenhui Rong, Zhichao Huang, Zhantao Peng, Zhen Xu, Junyi Zhou, Bin Di, Xiong Zhou, and Kai Wu. "Atomic structures and local electronic properties of K- and Rh-modified ceria/Pt(111) inverse model catalysts." Journal of Chemical Physics 151, no. 18 (November 14, 2019): 184703. http://dx.doi.org/10.1063/1.5128960.

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16

Králik, Milan, Roman Fišera, Marco Zecca, Angelo A. D'Archivio, Luciano Galantini, Karel Jeřábek, and Benedetto Corain. "Modelling of the Deactivation of Polymer-Supported Palladium Catalysts in the Hydrogenation of 4-Nitrotoluene." Collection of Czechoslovak Chemical Communications 63, no. 7 (1998): 1074–88. http://dx.doi.org/10.1135/cccc19981074.

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The kinetics of the hydrogenation of 4-nitrotoluene over Pd catalysts supported on sulfonated polystyrene and simultaneous deactivation of these catalysts were investigated. Reaction rates of both the hydrogenation and the dissolution of Pd crystallites were related to the total Pd surface. The average radius of ideal spherical crystallites, as determined by X-ray powder diffraction analysis, was taken as the starting value of the crystallite size. Stability of the polymer network was checked by Inverse Steric Exclusion Chromatography (ISEC). The ESR and Static Gradient field Spin Echo (SGSE) NMR spectroscopies were used to assess the accessibility and diffusivity before and after deactivation experiments. Langmuir-Hinshelwood type kinetic models were applied to describe the hydrogenation of 4-nitrotoluene. The kinetic law was incorporated into a more comprehensive model involving also diffusion of reactants inside catalytic particles. Simultaneous treatment of a few sets of kinetic data from batch hydrogenation carried out at 0.25-0.75 MPa yielded reliable values of model parameters. The model showed an increasing rate of dissolution of palladium with decreasing concentration of hydrogen and increasing concentration of 4-nitrotoluene. The latter fact supports the hypothesis that the nitro compound is the oxidant responsible for the dissolution of palladium.

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17

Krenn, G., J. Schoiswohl, S. Surnev, F. P. Netzer, and R. Schennach. "Metal-oxide boundary effects in vanadium oxide – Rh(111) inverse model catalysts: a RAIRS, STM and TPD study." Topics in Catalysis 46, no. 1-2 (September 2007): 231–38. http://dx.doi.org/10.1007/s11244-007-0333-5.

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18

Kang, Jindong, Mausumi Mahapatra, Ning Rui, Ivan Orozco, Rui Shi, Sanjaya D. Senanayake, and José A. Rodriguez. "Growth and structural studies of In/Au(111) alloys and InOx/Au(111) inverse oxide/metal model catalysts." Journal of Chemical Physics 152, no. 5 (February 7, 2020): 054702. http://dx.doi.org/10.1063/1.5139237.

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19

Zambaldi, Philipp, Leander Haug, Simon Penner, and Bernhard Klötzer. "Dry Reforming of Methane on NiCu and NiPd Model Systems: Optimization of Carbon Chemistry." Catalysts 12, no. 3 (March 9, 2022): 311. http://dx.doi.org/10.3390/catal12030311.

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A series of ultra-clean, unsupported Cu-doped and Pd-doped Ni model catalysts was investigated to develop the fundamental concept of metal doping impact on the carbon tolerance and catalytic activity in the dry reforming of methane (DRM). Wet etching with concentrated HNO3 and a subsequent single sputter–anneal cycle resulted in the full removal of an already existing oxidic passivation layer and segregated and/or ambient-deposited surface and bulk impurities to yield ultra-clean Ni substrates. Carbon solubility, support effects, segregation processes, cyclic operation temperatures, and electronic and ensemble effects were all found to play a crucial role in the catalytic activity and stability of these systems, as verified by X-ray photoelectron spectroscopy (XPS) surface and bulk characterization. Minor Cu promotion showed the almost complete suppression of coking with a moderate reduction in catalytic activity, while high Cu loadings facilitated carbon growth alongside severe catalytic deactivation. The improved carbon resistance stems from an increased CH4 dissociation barrier, decreased carbon solubility in the bulk, good prevailing CO2 activation properties and enhanced CO desorption. Cyclic DRM operation on surfaces with Cu content that is too high leads to impaired carbon oxidation kinetics by CO2 and causes irreversible carbon deposition. Thus, an optimal and stable NiCu composition was found in the region of 70–90 atomic % Ni, which allows an appropriate high syngas production rate to be retained alongside a total coking suppression during DRM. In contrast, the more Cu-rich NiCu systems showed a limited stability under reaction conditions, leading to undesired surface and bulk segregation processes of Cu. The much higher carbon deposition rate and solubility of unsupported NiPd and Pd model catalysts results in severe carbon deposition and catalytic deactivation. To achieve enhanced carbon conversion and de-coking, an active metal oxide boundary is required, allowing for the increased clean-off of re-segregated carbon via the inverse Boudouard reaction. The carbon bulk diffusion on the investigated systems depends strongly on the composition and decreases in the following order: Pd > NiPd > Ni > NiCu > Cu.

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20

Ali-Ahmad, Ali, Tayssir Hamieh, Thibault Roques-Carmes, Mohamad Hmadeh, and Joumana Toufaily. "Effect of Modulation and Functionalization of UiO-66 Type MOFs on Their Surface Thermodynamic Properties and Lewis Acid–Base Behavior." Catalysts 13, no. 1 (January 16, 2023): 205. http://dx.doi.org/10.3390/catal13010205.

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In this study, we investigated the surface thermodynamic properties of four MOF structures of the UiO-66 series, by employing seven molecular models, a thermal model, and three other methods using the inverse gas chromatography (IGC) technique at infinite dilution. We first determined the effect of the modulation of UiO-66 by an acid (e.g., formic acid and acetic acid) and on the other hand, we studied the effect of the functionalization of the organic linker by an amine group (NH2) on their dispersive component of the surface energy and on their Lewis acid–base properties. We found that all the studied MOFs presented an amphoteric character with a strong acidity whose acidity/basicity ratio is greater than 1 using all the models and methods in IGC. Moreover, the introduction of a modulator such as acetic acid or formic acid in the synthesis of these MOFs increased the number of structural defects and therefore increased the acidity of these MOFs. Similarly, the functionalization of the MOF by the NH2 group leads to an increase in the basicity constant of the functionalized MOF while remaining smaller than their acidity constant. In addition, the use of acids as modulators and amine groups as functional groups resulted in an increase in the dispersive component of the surface energy of the MOFs. Finally, comparing the results obtained by the different models and methods and based on the increasing order of the acidity of each MOF, it was clear that the thermal model resulted in more exact and precise values than the others. Our findings pave the way for the design and development of new acid catalysts based on UiO-66 structures.

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21

Гиззатова, Э. Р., А. Р. Шагиахметов, Г. К. Хисаметдинова, and С. Л. Подвальный. "CALCULATION OF THE RESIDUAL FUNCTION IN THE BASIS SPACE TO SEARCH FOR AREAS OF UNCERTAINTY OF THE RATE CONSTANTS OF THE POLYMERIZATION PROCESS." ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА, no. 4(-) (August 30, 2022): 37–43. http://dx.doi.org/10.36622/vstu.2022.18.4.005.

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Предлагаeтся к рассмотрению математическая модель процесса полимеризации на катализаторах Циглера-Натта, в предположении существования только трех элементарных стадий: роста полимерной цепи, передачи цепи на мономер и передачи цепи на алюминийорганическое соединение при условии отсутствия стадии инициирования активных центров. Приведены постановки прямой и обратной кинетической задач, последняя из которых заключается в поиске областей неопределенных для констант скоростей стадий роста и передач цепи. Показано, что для рассматриваемого процесса значения констант могут быть определены в базисном пространстве, построенном на векторах констант. В отличие от исходного трехмерного пространства базисное пространство позволяет рассчитывать и визуализировать сеточные поверхности по функции невязки для среднечисленной молекулярной массы. При условии расчета невязки как максимума отклонений или суммы квадратов отклонений получают разные поверхности. Показано, как наложение поверхностей друг на друга локализует области минимума, которые впоследствии можно характеризовать как решение обратных кинетических задач. При этом такой подход позволяет оценить форму и вид «овражных» минимумов и, в целом, определять оптимальные наборы констант, идентифицирующие точки минимума The paper proposes a mathematical model of the polymerization process on Ziegler-Natt catalysts, assuming the existence of only three elementary stages: the growth of the polymer chain, the transfer of the chain to the monomer and the transfer of the chain to the organoaluminium compound, provided there is no stage of initiation of active centers. We give the statements of direct and inverse kinetic problems, the latter of which consists in finding the regions of the chain growth stages and gears that are indeterminate for the rate constants. We show that for the process under consideration, the values of the constants can be determined in the basis space constructed on the vectors of the constants. Unlike the original three-dimensional space, the basis space allows calculating and visualizing grid surfaces by the residual function for the average calculated molecular weight. If the discrepancy is calculated as the maximum of deviations or the sum of the squares of deviations, different surfaces are obtained. We show the way the superposition of surfaces on each other localizes the minimum regions, which can subsequently be characterized as the solution of inverse kinetic problems. At the same time, this approach allows us to evaluate the shape and appearance of "gully" minima and, in general, to determine the optimal set of constants identifying the minimum points

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22

Ayala, A., M. Loewe, and R. Zamora. "Inverse magnetic catalysis in the linear sigma model." Journal of Physics: Conference Series 720 (May 2016): 012026. http://dx.doi.org/10.1088/1742-6596/720/1/012026.

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23

Allan, Michael, David Grinter, Simran Dhaliwal, Chris Muryn, Thomas Forrest, Francesco Maccherozzi, Sarnjeet S. Dhesi, and Geoff Thornton. "Redox behaviour of a ceria–zirconia inverse model catalyst." Surface Science 682 (April 2019): 8–13. http://dx.doi.org/10.1016/j.susc.2018.12.005.

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24

Pagura, V. P., D. Gomez Dumm, S. Noguera, and N. N. Scoccola. "Inverse magnetic catalysis in nonlocal chiral quark models." Journal of Physics: Conference Series 1024 (May 2018): 012042. http://dx.doi.org/10.1088/1742-6596/1024/1/012042.

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25

Schoiswohl, J., S. Surnev, and F. P. Netzer. "Reactions on Inverse Model Catalyst Surfaces: Atomic Views by STM." Topics in Catalysis 36, no. 1-4 (August 2005): 91–105. http://dx.doi.org/10.1007/s11244-005-7865-3.

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26

Гиззатова, Э. Р., С. Л. Подвальный, and С. И. Спивак. "SEARCH FOR KINETIC CONSTANTS IN MODELING THE PROCESSES OF POLYCENTERS NON-BREAK POLYMERIZATION OF DIENES." ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА, no. 5() (November 18, 2020): 13–18. http://dx.doi.org/10.36622/vstu.2020.16.5.002.

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Приводится методика решения обратной кинетической задачи поиска констант скоростей полимеризационного процесса для кинетически неоднородных каталитических систем Циглера-Натта. Неоднородность катализаторов рассматривается как существование нескольких типов активных центров, параллельно друг другу ведущих процессы роста и обрыва полимерных цепей. Кинетическая схема процесса исключает материальный обрыв цепи, что влечет передачу активности с одного центра на другой. Наблюдаемое условие постоянства концентрации активных центров является уравнением материального баланса полимеризационной системы. Оно соблюдается в математической модели, описывающей процесс в виде автономной системы, содержащей бесконечное число обыкновенных дифференциальных уравнений первого порядка по мономеру, преобразованной методом моментов к конечному виду. Отмечено, что статистические моменты, присутствующие в системе дифференциальных уравнений, являются начальными моментами молекулярно-массового распределения. На их основе даны аналитические зависимости для искомых средних молекулярных масс образующихся полимеров на каждом типе активных центров и всего полимерного образца. Расчетный эксперимент проведен для процесса полимеризации изопрена на 4-центровой ванадийсодержащей каталитической системе с целью получения решения обратной кинетической задачи. Найден совокупный набор констант скоростей элементарных стадий процесса. Показаны графические иллюстрации сравнений расчетов и экспериментов по значениям средних молекулярных масс по каждому типу активных центров и всего полимера в целом We present a technique for solving the inverse kinetic problem of finding the rate constants of the polymerization process for kinetically inhomogeneous catalytic systems of the Ziegler-Natta. We consider inhomogeneity of catalysts as the existence of several types of active centers, parallel to each other leading processes of growth and termination of polymer chains. The kinetic scheme of the process excludes material breaking of the chain, which entails the transfer of activity from one center to another. The observed condition for the constancy of the concentration of active centers is the material balance equation for the polymerization system. It is observed in a mathematical model that describes the process in the form of an autonomous system containing an infinite number of ordinary differential equations of the first order in monomer, transformed by the method of moments to a finite form. We note that the statistical moments present in the system of differential equations are the initial moments of the molecular weight distribution. On their basis, we give analytical dependences for the desired average molecular weights of the resulting polymers on each type of active centers and the entire polymer sample. We carried out a computational experiment for the process of isoprene polymerization on a 4-center vanadium-containing catalytic system in order to obtain a solution to the inverse kinetic problem. We found a cumulative set of rate constants for elementary stages of the process. We show graphical illustrations of comparisons of calculations and experiments on the values of the average molecular weights for each type of active site and the entire polymer as a whole

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27

Swanwick, Richard S., Giovanni Maglia, Lai-hock Tey, and Rudolf K. Allemann. "Coupling of protein motions and hydrogen transfer during catalysis by Escherichia coli dihydrofolate reductase." Biochemical Journal 394, no. 1 (January 27, 2006): 259–65. http://dx.doi.org/10.1042/bj20051464.

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The enzyme DHFR (dihydrofolate reductase) catalyses hydride transfer from NADPH to, and protonation of, dihydrofolate. The physical basis of the hydride transfer step catalysed by DHFR from Escherichia coli has been studied through the measurement of the temperature dependence of the reaction rates and the kinetic isotope effects. Single turnover experiments at pH 7.0 revealed a strong dependence of the reaction rates on temperature. The observed relatively large difference in the activation energies for hydrogen and deuterium transfer led to a temperature dependence of the primary kinetic isotope effects from 3.0±0.2 at 5 °C to 2.2±0.2 at 40 °C and an inverse ratio of the pre-exponential factors of 0.108±0.04. These results are consistent with theoretical models for hydrogen transfer that include contributions from quantum mechanical tunnelling coupled with protein motions that actively modulate the tunnelling distance. Previous work had suggested a coupling of a remote residue, Gly121, with the kinetic events at the active site. However, pre-steady-state experiments at pH 7.0 with the mutant G121V-DHFR, in which Gly121 was replaced with valine, revealed that the chemical mechanism of DHFR catalysis was robust to this replacement. The reduced catalytic efficiency of G121V-DHFR was mainly a consequence of the significantly reduced pre-exponential factors, indicating the requirement for significant molecular reorganization during G121V-DHFR catalysis. In contrast, steady-state measurements at pH 9.5, where hydride transfer is rate limiting, revealed temperature-independent kinetic isotope effects between 15 and 35 °C and a ratio of the pre-exponential factors above the semi-classical limit, suggesting a rigid active site configuration from which hydrogen tunnelling occurs. The mechanism by which hydrogen tunnelling in DHFR is coupled with the environment appears therefore to be sensitive to pH.

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28

Mayr, Lukas, Xue-Rong Shi, Norbert Köpfle, Cory A. Milligan, Dmitry Y. Zemlyanov, Axel Knop-Gericke, Michael Hävecker, Bernhard Klötzer, and Simon Penner. "Chemical vapor deposition-prepared sub-nanometer Zr clusters on Pd surfaces: promotion of methane dry reforming." Physical Chemistry Chemical Physics 18, no. 46 (2016): 31586–99. http://dx.doi.org/10.1039/c6cp07197j.

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29

Gómez Dumm, D., M. F. Izzo Villafañe, S. Noguera, V. P. Pagura, and N. N. Scoccola. "Strong magnetic fields in a nonlocal Polyakov chiral quark model." EPJ Web of Conferences 172 (2018): 02007. http://dx.doi.org/10.1051/epjconf/201817202007.

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We study the behavior of strongly interacting matter under an external constant magnetic field in the context of nonlocal chiral quark models that incorporate a coupling to the Polyakov loop. We find that at zero temperature the behavior of the quark condensates shows the expected magnetic catalysis effect, our predictions being in good quantitative agreement with lattice QCD results. On the other hand when the analysis is extended to the case of finite temperature our results show that nonlocal models naturally lead to the Inverse Magnetic Catalysis effect for both the chiral restoration and deconfinement transition temperatures.

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30

Mao, Shijun. "Inverse magnetic catalysis in Nambu–Jona-Lasinio model beyond mean field." Physics Letters B 758 (July 2016): 195–99. http://dx.doi.org/10.1016/j.physletb.2016.05.018.

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31

Shen, Yongli, and Zihui Xiao. "Reducible Inverse CeOx-Based Catalyst as a Potential Candidate for Electroreduction." Catalysts 9, no. 1 (December 29, 2018): 22. http://dx.doi.org/10.3390/catal9010022.

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The inverse metal oxide/metal catalyst is very suitable for electrochemical reaction due to unique catalytic properties of metal oxide with small size and good conductivity of metal. To clarify the potential applications of inverse catalyst in electrochemistry, especially for reducible oxides, an inverse CeOx/Ag(111) model electrocatalyst was constructed and investigated by Density Functional Theory (DFT) for CO2 electrochemical reduction. It is found that Ag atoms acting as an electron donor, can partially reduce Ce4+ to Ce3+ in the supported CeOx cluster leading to the formation of interfacial Ce3+ active sites, which could promote the adsorption and reduction of CO2. As expected, all elementary reaction involved in the CO2 electrochemical reduction are more facile on CeOx/Ag(111) than pure Ag catalyst. Besides, the generation of CH3OH and CH4 is favored on CeOx/Ag(111), whereas the formation of CO, CH2O and H2 is obviously suppressed. More importantly, the weak interaction between H2O and CeOx cluster is beneficial for the desorption of OH intermediate, which makes the regeneration of the catalyst become easier and result in a great recyclability. All those results demonstrate that CeOx/Ag(111) is a potential excellent electrochemical catalyst.

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32

Ayala, Alejandro, M. Loewe, C. Villavicencio, and R. Zamora. "On the magnetic catalysis and inverse catalysis of phase transitions in the linear sigma model." Nuclear and Particle Physics Proceedings 258-259 (January 2015): 209–12. http://dx.doi.org/10.1016/j.nuclphysbps.2015.01.045.

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33

Duarte, Dyana C., Pablo G. Allen, Ricardo L. S. Farias, Pedro H. A. Manso, and Norberto N. Scoccola. "Exploring the BEC-BCS Crossover in a Cold and Magnetized 2-Color QCD." International Journal of Modern Physics: Conference Series 45 (January 2017): 1760066. http://dx.doi.org/10.1142/s2010194517600667.

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We study the BEC-BCS crossover in the presence of an external magnetic field for a two color NJL model with diquark interactions, giving special attention to the regularization scheme. We found a inverse magnetic catalysis on the critical chemical potentials, both for BEC phase transition and the BEC-BCS crossover for small values of magnetic fields, and a magnetic catalysis for large [Formula: see text].

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34

Ahmad, A., and A. Raya. "Inverse magnetic catalysis and confinement within a contact interaction model for quarks." Journal of Physics G: Nuclear and Particle Physics 43, no. 6 (May 16, 2016): 065002. http://dx.doi.org/10.1088/0954-3899/43/6/065002.

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35

Fraga, E. S., B. W. Mintz, and J. Schaffner-Bielich. "A search for inverse magnetic catalysis in thermal quark–meson models." Physics Letters B 731 (April 2014): 154–58. http://dx.doi.org/10.1016/j.physletb.2014.02.028.

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36

Matolín, Vladimír, Libor Sedláček, Iva Matolínová, František Šutara, Tomáš Skála, Břetislav Šmíd, Jiří Libra, Václav Nehasil, and Kevin C. Prince. "Photoemission Spectroscopy Study of Cu/CeO2Systems: Cu/CeO2Nanosized Catalyst and CeO2(111)/Cu(111) Inverse Model Catalyst." Journal of Physical Chemistry C 112, no. 10 (March 2008): 3751–58. http://dx.doi.org/10.1021/jp077739g.

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37

Ngo, Son Ich, and Young-Il Lim. "Solution and Parameter Identification of a Fixed-Bed Reactor Model for Catalytic CO2 Methanation Using Physics-Informed Neural Networks." Catalysts 11, no. 11 (October 28, 2021): 1304. http://dx.doi.org/10.3390/catal11111304.

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In this study, we develop physics-informed neural networks (PINNs) to solve an isothermal fixed-bed (IFB) model for catalytic CO2 methanation. The PINN includes a feed-forward artificial neural network (FF-ANN) and physics-informed constraints, such as governing equations, boundary conditions, and reaction kinetics. The most effective PINN structure consists of 5–7 hidden layers, 256 neurons per layer, and a hyperbolic tangent (tanh) activation function. The forward PINN model solves the plug-flow reactor model of the IFB, whereas the inverse PINN model reveals an unknown effectiveness factor involved in the reaction kinetics. The forward PINN shows excellent extrapolation performance with an accuracy of 88.1% when concentrations outside the training domain are predicted using only one-sixth of the entire domain. The inverse PINN model identifies an unknown effectiveness factor with an error of 0.3%, even for a small number of observation datasets (e.g., 20 sets). These results suggest that forward and inverse PINNs can be used in the solution and system identification of fixed-bed models with chemical reaction kinetics.

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38

Tyrtygin, Vyacheslav N., Aleksey A. Deniskovets, and Aleksandr N. Labutin. "MATHEMATICAL AND STATISTICAL MODEL OF CLEANING IN A HIGH-GRADIENT MAGNETIC FIELD OF HYDROGENATED FAT FROM SUSPENDED CATALYST." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 64, no. 6 (May 16, 2021): 83–88. http://dx.doi.org/10.6060/ivkkt.20216406.6410.

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The introduction specifies the object of the study - hydrogenated fat subjected to purification from suspended nickel-containing catalyst in a high-gradient magnetic field. The nickel-containing catalyst, due to the presence of nickel salts in it, is paramagnetic and can be effectively extracted from hydrated fat in the magnetic field by a method of highly gradient magnetic separation. In the experiment technique the magnetic field strength was not less than 600 kA/m, the gradient not less than (20-30)∙104 kA/m2. Based on the results and their discussion, the analysis of empirical dependencies on each factor basis is carried out separately, as well as the construction of classical types of one-dimensional non-linear regression models for each of them. It is shown that the most statistically reliable are the exponential models. It was found that after purification the content of suspended nickel-containing catalyst in the hydrogenated fat has an inverse proportional dependence on the magnetic field strength, height (length) of the filtration zone and filtration rate. A two-dimensional exponential regression model of the content of the nickel-containing catalyst in the hydrogenated fat in the complex dependence on the rate and height of the filtration zone is built. Based on the experimental data at a certain height of the filtration zone and the selected filtration rate, a mathematical-statistical model of change in the concentration of nickel-containing catalyst depending on the magnetic field strength is made. Using the resulting two-dimensional exponential regression model, it is possible to predict the degree of purification of the salomas from the suspended catalyst depending on the specific tension of the magnetic field and to determine the tension of the magnetic field, at which the concentration of nickel as a result of cleaning will reach an advance value.

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39

Tawfik, Abdel Nasser, Abdel Magied Diab, Nada Ezzelarab, and Asmaa G. Shalaby. "QCD Thermodynamics and Magnetization in Nonzero Magnetic Field." Advances in High Energy Physics 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/1381479.

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In nonzero magnetic field, the magnetic properties and thermodynamics of the quantum-chromodynamic (QCD) matter are studied in the hadron resonance gas and the Polyakov linear-sigma models and compared with recent lattice calculations. Both models are fairly suited to describe the degrees of freedom in the hadronic phase. The partonic ones are only accessible by the second model. It is found that the QCD matter has paramagnetic properties, which monotonically depend on the temperature and are not affected by the hadron-quark phase transition. Furthermore, raising the magnetic field strength increases the thermodynamic quantities, especially in the hadronic phase, but reduces the critical temperature, that is, inverse magnetic catalysis.

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40

Barroo, Cédric, Zhu-Jun Wang, and Marc Georg Willinger. "Imaging Reaction Dynamics on Inverse Model Catalyst Surfaces by In Situ Environmental SEM." Microscopy and Microanalysis 25, S2 (August 2019): 510–11. http://dx.doi.org/10.1017/s1431927619003283.

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41

Surnev, S., M. Sock, G. Kresse, J. N. Andersen, M. G. Ramsey, and F. P. Netzer. "Unusual CO Adsorption Sites on Vanadium Oxide−Pd(111) “Inverse Model Catalyst” Surfaces." Journal of Physical Chemistry B 107, no. 20 (May 2003): 4777–85. http://dx.doi.org/10.1021/jp0223408.

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42

Corrêa, Emerson B. S., César A. Linhares, and Adolfo P. C. Malbouisson. "A model to study finite-size and magnetic effects on the phase transition of a fermion interacting system." International Journal of Modern Physics B 32, no. 08 (March 13, 2018): 1850091. http://dx.doi.org/10.1142/s0217979218500911.

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We present a model to study the effects from external magnetic field, chemical potential and finite size on the phase structures of a massive four- and six-fermion interacting systems. These effects are introduced by a method of compactification of coordinates, a generalization of the standard Matsubara prescription. Through the compactification of the z-coordinate and of imaginary time, we describe a heated system with the shape of a film of thickness L, at temperature [Formula: see text] undergoing first- or second-order phase transition. We have found a strong dependence of the temperature transition on the coupling constants [Formula: see text] and [Formula: see text]. Besides inverse magnetic catalysis and symmetry breaking for both kinds of transition, we have found an inverse symmetry breaking phenomenon with respect to first-order phase transition.

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43

Eck, S., C. Castellarin-Cudia, S. Surnev, K. C. Prince, M. G. Ramsey, and F. P. Netzer. "Adsorption and reaction of CO on a ceria–Rh(111) “inverse model catalyst” surface." Surface Science 536, no. 1-3 (June 2003): 166–76. http://dx.doi.org/10.1016/s0039-6028(03)00594-6.

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44

Magkoev, Tamerlan T. "Interaction of carbon monoxide and oxygen at the surface of inverse titania/Au model catalyst." Surface Science 601, no. 14 (July 2007): 3143–48. http://dx.doi.org/10.1016/j.susc.2007.05.015.

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45

Köpfle, Norbert, Kevin Ploner, Peter Lackner, Thomas Götsch, Christoph Thurner, Emilia Carbonio, Michael Hävecker, et al. "Carbide-Modified Pd on ZrO2 as Active Phase for CO2-Reforming of Methane—A Model Phase Boundary Approach." Catalysts 10, no. 9 (September 2, 2020): 1000. http://dx.doi.org/10.3390/catal10091000.

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Starting from subsurface Zr0-doped “inverse” Pd and bulk-intermetallic Pd0Zr0 model catalyst precursors, we investigated the dry reforming reaction of methane (DRM) using synchrotron-based near ambient pressure in-situ X-ray photoelectron spectroscopy (NAP-XPS), in-situ X-ray diffraction and catalytic testing in an ultrahigh-vacuum-compatible recirculating batch reactor cell. Both intermetallic precursors develop a Pd0–ZrO2 phase boundary under realistic DRM conditions, whereby the oxidative segregation of ZrO2 from bulk intermetallic PdxZry leads to a highly active composite layer of carbide-modified Pd0 metal nanoparticles in contact with tetragonal ZrO2. This active state exhibits reaction rates exceeding those of a conventional supported Pd–ZrO2 reference catalyst and its high activity is unambiguously linked to the fast conversion of the highly reactive carbidic/dissolved C-species inside Pd0 toward CO at the Pd/ZrO2 phase boundary, which serves the role of providing efficient CO2 activation sites. In contrast, the near-surface intermetallic precursor decomposes toward ZrO2 islands at the surface of a quasi-infinite Pd0 metal bulk. Strongly delayed Pd carbide accumulation and thus carbon resegregation under reaction conditions leads to a much less active interfacial ZrO2–Pd0 state.

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46

Providência, C., M. Ferreira, and P. Costa. "Inverse Magnetic Catalysis in the Polyakov--Nambu--Jona-Lasinio and Entangled Polyakov--Nambu--Jona-Lasinio Models." Acta Physica Polonica B Proceedings Supplement 8, no. 1 (2015): 207. http://dx.doi.org/10.5506/aphyspolbsupp.8.207.

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47

He, Lichao, Zhiliang Cui, Xiangchun Sun, Jin Zhao, and Dongsheng Wen. "Sensitivity Analysis of the Catalysis Recombination Mechanism on Nanoscale Silica Surfaces." Nanomaterials 12, no. 14 (July 11, 2022): 2370. http://dx.doi.org/10.3390/nano12142370.

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A deep understanding of surface catalysis recombination characteristics is significant for accurately predicting the aeroheating between hypersonic non-equilibrium flow and thermal protection materials, while a de-coupling sensitivity analysis of various influential factors is still lacking. A gas–solid interface (GSI) model with a hyperthermal flux boundary was established to investigate the surface catalysis recombination mechanisms on nanoscale silica surfaces. Using the reactive molecular dynamics (RMD) simulation method, the effects of solid surface temperature, gas incident angle, and translational energy on the silica surface catalysis recombination were qualified under hyperthermal atomic oxygen (AO), atomic nitrogen (AN), and various AN/AO gas mixtures’ influence. It can be found that, though the Eley–Rideal (E–R) recombination mechanism plays a dominant role over the Langmuir–Hinshelwood (L–H) mechanism for all the sensitivity analyses, a non-linear increasing pattern of AO recombination coefficient γO2 with the increase in incident angle θin and translational energy Ek is observed. Compared with the surface catalysis under hyperthermal AO impact, the AN surface adsorption fraction shows an inverse trend with the increase in surface temperature, which suggests the potential inadequacy of the traditional proportional relationship assumptions between the surface adsorption concentration and the surface catalysis recombination coefficient for other species’ impact instead of AOs. For the incoming bi-component AO/AN gas mixtures, the corresponding surface catalysis coefficient is not the simple superposition of the effects of individual gases but is affected by both the intramolecular bond energies (e.g., O2, N2) and intermolecular energies (e.g., Si/N, Si/O).

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48

Rameshan, C., H. Li, K. Anic, M. Roiaz, V. Pramhaas, R. Rameshan, R. Blume, et al. "In situ NAP-XPS spectroscopy during methane dry reforming on ZrO2/Pt(1 1 1) inverse model catalyst." Journal of Physics: Condensed Matter 30, no. 26 (June 8, 2018): 264007. http://dx.doi.org/10.1088/1361-648x/aac6ff.

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49

Perczel, András, Ödön Farkas, Imre G. Csizmadia, and Attila G. Császar. "Peptide models XX. Aromatic side-chain–backbone interaction in phenylalanine-containing diamide model system. A systematic search for the identification of all the ab initio conformers of N-formyl-L-phenylalanine-amide." Canadian Journal of Chemistry 75, no. 8 (August 1, 1997): 1120–30. http://dx.doi.org/10.1139/v97-134.

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Phenylalanine is the simplest among the four natural amino acid residues that have aromatic side chains. The ab initio conformational analysis performed at the RHF/3-21G level on a phenylalanine-containing diamide model system (N-Formyl-L-Phe-NH2) revealed 19 different structures. Single-point energy calculations were performed using RHF/6-31+G* and DFT(B3LYP)/6-311++G** levels for all conformers. The inverse (γL) and the normal (γD) gamma turn, the extended (βL), the left-handed helical [Formula: see text], and the inverse polyproline II [Formula: see text] backbone conformers each have three (g+, a, and g−) side-chain (χ1,) rotamers. The [Formula: see text] and the [Formula: see text] type main-chain conformers have only two side-chain orientations, respectively. No minima have been found for the conformational building unit of the right-handed helical [Formula: see text] and for the polyproline II [Formula: see text] structures. The present ab initio conformational analysis for For-L-Phe-NH2 is a unique example in which a systematic and complete conformational set was established for a diamide system with an aromatic side chain. Analytic vibrational frequency calculations were established for all stationary points found as minima on the potential energy surface. These data may be used in the future as reference conformers in more detailed vibrational and (or) chemical shielding calculations or during the structural analysis of peptides and proteins by X-ray or NMR techniques. Keywords: ab initio peptide conformers, all RHF/3-21G structures of For-L-Phe-NH2, backbone – side-chain interaction in phenylalanine-containing peptide models.

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50

Ravasco, Joao M. J. M., and Jaime A. S. Coelho. "Predictive Multivariate Models for Bioorthogonal Inverse-Electron Demand Diels–Alder Reactions." Journal of the American Chemical Society 142, no. 9 (February 14, 2020): 4235–41. http://dx.doi.org/10.1021/jacs.9b11948.

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