Cascading Water Activation and Interfacial Lattice Oxygen over Nanocluster CuO_x‐Modified MnO₂ for Electrocatalytic Propylene Oxidation

Abstract Direct electrooxidation of propylene using water‐oxidation intermediates represents a promising route for propylene glycol production. Unfortunately, this economic and environmentally friendly process suffers from low yield and poor Faradaic efficiency resulting from the mismatched oxidative capacity of reactive oxygen species and pronounced side reactions. Herein, we developed an earth‐abundant metal‐based nanocluster CuO x ‐modified MnO 2 catalyst for the efficient electrooxidation of propylene into propylene glycol, achieving a remarkable production rate of 63.0 g/m 2 /h and 95 % Faradaic efficiency at 1.3 V vs. Ag/AgCl. Mechanistic studies revealed that the oxygen vacancy‐mediated water activation on CuO x ‐MnO 2 in synergy with the activated interfacial lattice oxygen drove the propylene oxidation to a novel *OOH pathway rather than the traditional *OH route. Additionally, the interfacial interactions intensified the propylene adsorption and polarization for its activation. This work offers new insights into the mechanism of electrocatalytic propylene oxidation and presents great opportunities for the synthesis of commercial chemicals based on earth‐abundant metal catalysts and renewable electricity‐driven route.