Can N, S Cocoordination Promote Single Atom Catalyst Performance in CO2RR? Fe‐N2S2 Porphyrin versus Fe‐N4 Porphyrin

Abstract Single atom catalysts (SACs) are promising electrocatalysts for CO 2 reduction reaction (CO 2 RR), in which the coordination environment plays a crucial role in intrinsic catalytic activity. Taking the regular Fe porphyrin (Fe‐N 4 porphyrin) as a probe, the study reveals that the introduction of opposable S atoms into N coordination (Fe‐N 2 S 2 porphyrin) allows for an appropriate electronic structural optimization on active sites. Owing to the additional orbitals around the Fermi level and the abundant Fe orbital occupation after S substitution, N, S cocoordination can effectively tune SACs and thus facilitating protonation of intermediates during CO 2 RR. CO 2 RR mechanisms lead to possible C1 products via two‐, six‐, and eight‐electron pathways are systematically elucidated on Fe‐N 4 porphyrin and Fe‐N 2 S 2 porphyrin. Fe‐N 4 porphyrin yields the most favorable product of HCOOH with a limiting potential of −0.70 V. Fe‐N 2 S 2 porphyrin exhibits low limiting potentials of −0.38 and −0.40 V for HCOOH and CH 3 OH, respectively, surpassing those of most Cu‐based catalysts and SACs. Hence, the N, S cocoordination might provide better catalytic environment than regular N coordination for SACs in CO 2 RR. This work demonstrates Fe‐N 2 S 2 porphyrin as a high‐performance CO 2 RR catalyst, and highlights N, S cocoordination regulation as an effective approach to fine tune high atomically dispersed electrocatalysts.