Elucidation of the Synergistic Effect of Dopants and Vacancies on Promoted Selectivity for CO<sub>2</sub> Electroreduction to Formate
Zhongjian Li, Ang Cao, Qiang Zheng, Yuanyuan Fu, Tingting Wang, K. Thanigai Arul, Jeng‐Lung Chen, Bin Yang, Nadia Mohd Adli, Lecheng Lei, Chung‐Li Dong, Jianping Xiao, Gang Wu, Yang Hou
Abstract
Abstract Sn‐based materials are identified as promising catalysts for the CO 2 electroreduction (CO2RR) to formate (HCOO − ). However, their insufficient selectivity and activity remain grand challenges. A new type of SnO 2 nanosheet with simultaneous N dopants and oxygen vacancies ( V O ‐rich N‐SnO 2 NS) for promoting CO 2 conversion to HCOO − is reported. Due to the likely synergistic effect of N dopant and V O , the V O ‐rich N‐SnO 2 NS exhibits high catalytic selectivity featured by an HCOO − Faradaic efficiency (FE) of 83% at − 0.9 V and an FE of > 90% for all C1 products (HCOO − and CO) at a wide potential range from −0.9 to − 1.2 V. Low coordination Sn–N moieties are the active sites with optimal electronic and geometric structures regulated by V O and N dopants. Theoretical calculations elucidate that the reaction free energy of HCOO* protonation is decreased on the V O ‐rich N‐SnO 2 NS, thus enhancing HCOO − selectivity. The weakened H* adsorption energy also inhibits the hydrogen evolution reaction, a dominant side reaction during the CO2RR. Furthermore, using the catalyst as the cathode, a spontaneous Galvanic Zn‐CO 2 cell and a solar‐powered electrolysis process successfully demonstrated the efficient HCOO − generation through CO 2 conversion and storage.