Regulating the electrocatalytic active centers for accelerated proton transfer towards efficient CO reduction.

The electrochemical CO reduction reaction (CORR) is an important application that can considerably mitigate environmental and energy crises. However, the slow proton-coupled electron transfer process continues to limit overall catalytic performance. Fine-tuning the reaction microenvironment by accurately constructing the local structure of catalysts provides a novel approach to enhancing reaction kinetics. Here, cubic-phase α-MoC nanoparticles were incorporated into a carbon matrix and coupled with cobalt phthalocyanine molecules (α-MoC-CoPc@C) for the co-reduction of CO and HO, achieving an impressive Faradaic efficiency for CO close to 100%. Through a combination of spectroscopies, electrochemical measurements, and theoretical simulations, it is demonstrated that α-MoC nanoparticles and CoPc molecules with optimized local configuration serve as the active centers for HO activation and CO reduction, respectively. The interfacial water molecules were rearranged, forming a dense hydrogen bond network on the catalyst surface. This optimized microenvironment at the electrode-electrolyte interface synergistically enhanced water dissociation, accelerated proton transfer, and improved the overall performance of CORR.