Proton capture strategy for enhancing electrochemical CO2 reduction on atomically dispersed metal-nitrogen active sites

Electrocatalysts play a key role in accelerating the sluggish electrochemical CO₂ reduction (ECR) involving multi-electron and proton transfer. Herein, we develop a proton capture strategy via accelerating the water dissociation reaction catalyzed by transition metal nanoparticles (NPs) adjacent to atomically dispersed Ni-N_x active sites (Ni@NiNCM) to accelerate the proton transfer to the latter for boosting the intermediate protonation step, and hence the whole ECR process. For the first time, the accelerated protonation process is amply demonstrated experimentally. Aberration-corrected scanning transmission electron microscopy and synchrotron radiation X-ray absorption spectroscopy, together with DFT calculations, revealed that the Ni NPs accelerated the adsorbed H (H_ad) generation and transfer to the adjacent Ni-N_x sites for boosting the intermediate protonation and the overall ECR processes. This proton capture strategy is highly general, which can be extended to the design and preparation of various high-performance catalysts for diverse electrochemical reactions even beyond ECR.