Achieving efficient electroreduction of CO2 to CO in a wide potential window by encapsulating Ni nanoparticles in N-doped carbon nanotubes

Abstract

Developing efficient and stable catalysts for electrochemical CO2 reduction reaction (CO2RR) in a wide potential window is highly desirable for achieving carbon neutrality, but remains greatly challenging. Herein, we demonstrate a facile synthetic strategy to synthesize transition metal nickel-nitrogen-carbon (Ni-N-C) catalyst where nickel nanoparticles have been in-situ encapsulated into N-doped carbon nanotubes (Ni@NCNT) for CO2RR. Strikingly, the as-prepared Ni@NCNT catalyst shows a high CO Faradaic efficiency (>90%) in a wide potential range of −0.65 to −1.0 V versus reversible hydrogen electrode (vs. RHE), a large current density of 16.3 mA cm−2 at −0.8 V vs. RHE and robust durability after a continuous electroreduction of 18 h. Density functional theory calculations suggest that compared to pure Ni (111) and Ni nanoparticles-free solid N-doped carbon nanorods (NCNR), Ni@NCNT can more effectively suppress H2 evolution and stabilize ∗COOH intermediates without influencing ∗CO desorption, thus, giving rise to high activity and desirable selectivity toward CO2RR.