(665g) Phase-Dependent Promoting Effect of Surface Oxygen on Molybdenum Carbide Catalysts during Formic Acid Electrooxidation
AIChE Annual Meeting
2023
2023 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Electrocatalysis & Photocatalysis II: Electrocatalytic Materials
Tuesday, November 7, 2023 - 10:00am to 10:20am
In this work, we employ a combination of density functional theory (DFT), ab initio thermodynamics, and reaction rate theory to unravel the source of TMC catalytic activity in oxidation reactions. We investigate a model reaction system, namely formic acid electrooxidation on the meta-stable α-MoC1-x phase, which was selected based on its reported excellent catalytic activity in low-temperature water-gas shift and methanol oxidation. The kinetics-cognizant surface Pourbaix diagram that we developed reveals in situ surface modification at varying electrochemical conditions. The origin of α-MoC1-x high catalytic activity is attributed to unique oxycarbide motifs which weaken otherwise strong surface-adsorbate interactions as supported by the calibrated Bader charge analysis and energy decomposition analysis. We hypothesize that this counterintuitive promotional effect of in situ-deposited surface oxygen may be present in a range of electrocatalytic and thermocatalytic reactions on other TMCs.
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