Oldman

The porous hierarchical Ni/N/C single-site catalyst is synthesized by a convenient assembly-pyrolysis route on mesostructured template. The abundant micropores facilitate the formation of numerous high-active edge-hosted Ni-N₄ sites and the interconnected macro/mesopores much promote the mass transfer. The so-constructed catalyst demonstrates excellent catalytic activity with industrial-level CO partial current density of and ultra-wide potential plateau of high CO faradic efficiency.

Abstract

The practical applications of CO₂ electroreduction to CO driven by renewable electricity should simultaneously meet the requests of industrial-level CO partial current density (J_CO) at least 100 mA cm⁻², wide potential window of high CO faradic efficiency (FE_CO), and low cost. Herein, a new strategy is reported to construct porous hierarchical Ni/N/C single-site catalyst with excellent catalytic activity via coating Ni-containing ZIF-8 on mesostructured basic magnesium carbonate template followed by pyrolysis. The abundant micropores facilitate the formation of numerous edge-hosted Ni-N₄ sites with high intrinsic activity, and the interconnected macro/mesopores much promote CO₂ delivery and CO release for the full expression of intrinsic activity. Consequently, the catalyst exhibits the industrial-level J_CO of 105–462 mA cm⁻² at the potential range of −0.6∼−1.3 V with ultra-wide high FE_CO plateau (>90%@−0.4∼−1.3 V), showing great promise for practical application. This study provides a general synthetic strategy to explore high-performance hierarchical M/N/C electrocatalysts.