(N, B) Dual Heteroatom-Doped Hierarchical Porous Carbon Framework for Efficient Electroreduction of Carbon Dioxide

A versatile salt–sugar method is developed to synthesize a (N, B) dual heteroatom-doped three-dimensional (3D) hierarchical porous carbon network. Through freeze drying and a two-stage heating process, the N and B atoms can be atomically dispersed into the carbon structure with high doping levels (N, 10.2 at. %; B, 8.86 at. %). The as-prepared metal-free catalyst exhibit a high CO2-to-CO Faradaic efficiency of 83% at a low overpotential of 290 mV and an excellent stability for >20 h. The excellent performance of the catalyst is attributed to the synergistic catalytic effect from the N and B atom codoping and the 3D hierarchical porous structure. This work opens up enormous opportunities for multiheteroatom-doped porous carbon as catalysts for high-efficiency CO2 reduction and a range of electrochemical applications.