Hierarchical Dual Single-Atom Catalysts with Coupled CoN4 and NiN4 Moieties for Industrial-Level CO2 Electroreduction to Syngas

Renewable-driven electrochemical CO 2 reduction reaction (CO 2 RR) to syngas is an encouraging alternative strategy to traditional fossil fuel-based syngas production, and the development of industrial-level electrocatalysts is vital. Herein, based on theoretical optimization of metal species, hierarchical Co x Ni 1– x –N–C dual single-atom catalyst (DSAC) with individual NiN 4 (CO preferential) and CoN 4 (H 2 preferential) moieties was constructed by a two-step pyrolysis route. The Co 0.5 Ni 0.5 –N–C exhibits a stable CO Faradaic efficiency of 50 ± 5% and an industrial-level current density of 101–365 mA cm –2 in an ultrawide potential window of −0.5 to −1.1 V. The CO/H 2 ratio of syngas can be conveniently tuned by regulating the Co/Ni ratio. The coupled effect of NiN 4 and CoN 4 moieties under a local high-pH microenvironment is responsible for the regulation of the CO/H 2 selectivity and yield for the Co x Ni 1– x –N–C catalyst, which is not present in the mixed Co–N–C and Ni–N–C catalyst. This study provides a promising DSAC strategy for achieving industrial-level syngas production via CO 2 RR.