![]() ![]() The oxygen vacancies left behind must be reoxidized by reacting with molecular O 2 before another reactant molecule can be converted. The loss of the lattice O leads to the creation of O vacancies and results in the partial reduction of the oxide catalyst. A “Mars–van Krevelen” (MvK)-type mechanism is generally used to describe the kinetics of oxide-catalyzed oxidation reactions, where lattice oxygen (O) in the oxide is actively consumed by reacting with an adsorbed reactant to form oxygenated products that desorb from the surface ( 1, 2). By differentiating the chemical functionality between lattice oxygen and peroxide, these results are closely relevant to a wide range of catalytic oxidation reactions using excessively adsorbed oxygen to activate lattice oxygen and tune the activity and selectivity of redox sites.Ĭatalytic oxidation reactions cover a large part of the heterogeneous catalysis field, accounting for more than 60% of the chemicals and intermediates used in the chemical industry and playing a vital part in the remediation of hydrocarbon pollutants and the production of sustainable energy. ![]() Together with atomistic modeling, we identify that this opposite effect of the peroxide on the two oxidation reactions stems from its modification on coordinately unsaturated sites of the oxide surface. Using CuO as an example, we show that a surface layer of peroxide species acts as a promotor to significantly enhance CuO reducibility in favor of H 2 oxidation but conversely as an inhibitor to suppress CuO reduction against CO oxidation. Herein, we demonstrate the tunability of this separation with peroxide species formed by excessively adsorbed oxygen, thereby modifying the catalytic activity and selectivity of the oxide. The Mars–van Krevelen mechanism is the foundation for oxide-catalyzed oxidation reactions and relies on spatiotemporally separated redox steps. ![]()
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