Microenvironmental Effects on CO ₂ Hydrogenation Over PdZn Alloy Catalysts

Abstract Understanding catalytic reactions under realistic gas‐phase conditions is essential for the computational design of next‐generation industrial catalysts with enhanced efficiency and selectivity. In this work, a hybrid quantum/classical framework is employed to systematically investigate the effects of partial pressure, temperature, and surface coverage on CO ₂ hydrogenation over PdZn alloy catalysts. The multiscale approach incorporates local gas‐phase densities and realistic catalyst structures, enabling accurate prediction of reaction selectivity across operating conditions. The results reveal a temperature‐dependent shift in pressure response: at low temperatures, increasing pressure favors the COOH pathway, while at elevated temperatures, the HCOO pathway becomes more competitive as pressure increases. This opposite trend reflects a competition of long‐range and short‐range interactions between gas molecules and intermediates, which evolves nonlinearly with the system pressure. The surface structure further modulates catalyst‐environment interactions by altering local gas accessibility, for example, through suppressing CO ₂ adsorption while promoting the catalyst binding of smaller molecules like H ₂ . These findings provide a detailed mechanistic understanding of how catalyst structure and reaction environment jointly regulate free‐energy pathways in CO ₂ hydrogenation. The transferable strategy of integrating microenvironmental effects into first‐principles modeling advances the rational design of catalytic systems for efficient CO ₂ utilization and broader chemical transformations.