Coordination Environment Engineering to Regulate the Adsorption Strength of Intermediates in Single Atom Catalysts for High-performance CO 2 Reaction Reduction.

The modulation of the coordination environment of single atom catalysts (SACs) plays a vital role in promoting CO 2 reduction reaction (CO 2 RR). Herein, N or B doped Fe-embedded graphyne (Fe-GY), Fe-nXGYm (n = 1, 2, 3; X = N, B; m = 1, 2, 3), are employed as probes to reveal the effect of the coordination environment engineering on CO 2 RR performance via heteroatom doping in SACs. The results show that the doping position and number of N or B in Fe-GY significantly affects catalyst activity and CO 2 RR product selectivity. In comparison, Fe-1NGY exhibits high-performance CO 2 RR to CH 4 with a low limiting potential of -0.17 V, and Fe-2NGY3 is demonstrated as an excellent CO 2 RR electrocatalyst for producing HCOOH with a low limiting potential of -0.16 V. With applied potential, Fe-GY, Fe-1NGY, and Fe-2NGY3 exhibit significant advantages in CO 2 RR to CH 4 while hydrogen evolution reaction is inhibited. The intrinsic essence analysis illustrates that heteroatom doping modulates the electronic structure of active sites and regulates the adsorption strength of the intermediates, thereby rendering a favorable coordination environment for CO 2 RR. This work highlights Fe-nXGYm as outstanding SACs for CO 2 RR, and provides an in-depth insight into the intrinsic essence of the promotion effect from heteroatom doping.