Promoting the activity and selectivity of Ni sites via chemical coordination with pyridinic nitrogen for CO_2-to-CO electrochemical catalysis

摘要

Hybrid catalysts composed of transition metals and nitrogen-doped carbons have been emerging as one of efficient electrocatalysts for electrochemical CO2-to-CO under ambient conditions. Herein, NiO loaded on mesoporous graphene with tunable concentration of pyridinic nitrogen is rationally synthesized by using low-intensity pulsed laser irradiation and pyrolysis treatments. Comprehensive experiments verify that, it is pyridinic N, rather than pyrrolic N, when bonded to Ni, that significantly enhance the electrochemical CO2 reduction reaction performance. The optimized catalyst exhibits a high CO Faradaic efficiency of 87.5% at a low potential of -0.74 V vs. reversible hydrogen electrode, associated with negligible attenuation of continuous operation over 12 h. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.