Promoting industrial-level CO2 electroreduction kinetics via accelerating proton feeding on a metal-free aerogel electrocatalyst

Abstract

Developing cost-effective carbon based electrocatalysts with high activity and selectivity for CO2 reduction reaction (CO2RR) at industrial current density still remains challenges. Herein, we present a metal-free 3D cross-linked carbon aerogel catalyst containing homogeneously dispersed N and P sites (P@NCA) synthesized via freeze drying and subsequent carbonization. Benefit from the synergistic effect of N and P atoms, P@NCA aerogel delivers an excellent CO2RR activity featured by a wide potential window from − 0.3 V to − 0.9 V with CO Faradaic efficiency (FE) of above 90 %. Importantly, a high CO FE of 85 % at an industrial current density of 100 mA cm−2 is realized. Experimental explorations and in-situ spectroelectrochemistry analyses reveal that pyrrolic-N species acts as the real active site to execute CO2RR, while the P species facilitates the protonation process of *CO2 to *COOH intermediate by accelerating the proton feeding from water dissociation. Theoretical calculations demonstrate a suppressed *H adsorption and a facilitated *CO desorption step on pyrrolic-N site with P doping, boosting the whole CO2RR process. Further, a rechargeable Zn-CO2 battery constructed with P@NCA aerogel as cathode delivers a maximal power density of 0.8 mW cm−2 and a superior stability.