Regulating the electrocatalytic active centers for accelerated proton transfer towards efficient CO2 reduction

The electrochemical CO₂ reduction reaction (CO₂RR) 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_1-x nanoparticles were incorporated into a carbon matrix and coupled with cobalt phthalocyanine molecules (α-MoC_1-x-CoPc@C) for the co-reduction of CO₂ and H₂O, achieving an impressive Faradaic efficiency for CO close to 100%. Through a combination of <i>in-situ</i> spectroscopies, electrochemical measurements, and theoretical simulations, it is demonstrated that α-MoC_1-x nanoparticles and CoPc molecules with optimized local configuration serve as the active centers for H₂O activation and CO₂ 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 CO₂RR.