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We investigate the existence, uniqueness, and long-time behavior of classical solutions to a coupled system of seven nonlinear parabolic equations. Four of them are determined in the interior of a region, and the other three are solved on a part of the boundary. In particular, such systems arise in modeling of surface reactions that involve the bulk diffusion of reactants toward and reaction products from the biocatalyst surface and surface diffusion of the intermediate reaction products. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to investigate the existence, uniqueness, and long-time behaviour of classical solutions to a system composed of four quasilinear parabolic and three nonlinear ordinary differential equations arising in modelling of surface chemical reactions. Parabolic differential equations are solved in a domain, while the ordinary differential equations are considered on the boundary. In particular, such systems describe the enzyme-catalyzed glucose oxidation with dissolved oxygen proceeding over catalytic (enzyme-modified) surfaces. [ABSTRACT FROM AUTHOR]

VO2is well known for its reversible transition between two phases with tetragonal rutile and monoclinic structure. In a previous theoretical study (Stahl and Bredow 2022 ChemPhysChem 23 e202200131) we showed that the adsorption energy of CO is different on surfaces of the two Mo-stabilized polymorphs. This can be exploited to promote catalytic reactions by removing CO from the catalyst surface. As proof-of-principle, we investigated the hydrogenation reaction ofCO2. For this purpose, the adsorption energies ofCO2and possible intermediates and productsH2O, HCOOH,H2COand CO were calculated. Significant differences were found for the reaction energies of the hydrogenation ofCO2to formic acid and formaldehyde on the two polymorphs. This shows that it is in principle possible to alter the reaction thermodynamics by applying reaction conditions which stabilize a particular polymorph. In order to investigate the influence of the polymorph on kinetic properties, the reactions barriers of a step-wise reaction ofCO2+2H2→H2CO+H2Owas calculated using the nudged elastic band method.VO2was found to reduce the reaction barriers compared to the gas phase. Additionally, the minimum energy path of the bulk phase transition of undopedVO2was calculated using the distinguished reaction coordinate method. A catalytic cycle exploiting the phase transition is proposed based on the theoretical results., (© 2024 IOP Publishing Ltd.)