Ni/N-modulated biomass pyrolysis to make carbon-based catalysts for electrochemical CO2-to-CO conversion

Abstract

There are tremendous requirements in CO2 electrolysis to produce value-added chemicals, where the functional carbon-based catalysts possess the unique superiorities for CO2 conversion. Pyrolysis kinetics as a theoretical guidance is pivotal to construct the high-activity carbon-based catalysts precisely, which is decoupled urgently. Herein, the pyrolysis behaviors of ipomea batatas leaves were well optimized by Ni/N modulators and unveiled systematically, where the residence time of biomass was prolonged during the pyrolysis process and the emerged out-of-plane orientation sp3 C–N species were increased. Additionally, the presented first-order kinetics revealed that with Ni/N modulators, the higher apparent energy barrier was determined than single biomass, corresponding to an enhanced thermostability. As a guidance, the derivative catalyst with high N content (17.22 at%) can drive electrochemical CO2-to-CO reaction efficiently. The current density was up to 200 mA cm–2 and the CO Faradaic efficiency kept over 95 % at a wide work window (–0.66 to –1.46 V versus reversible hydrogen electrode) in flow cell.