Ruthenium-doped boron nitride nanotubes as promising electrocatalysts for carbon dioxide reduction to methane

Exploring low-cost and high-activity electrocatalysts for carbon dioxide reduction reaction (CO2RR) is necessary to reduce carbon dioxide emissions and alleviate the energy crisis. In this work, the catalytic performance of ruthenium doping into boron nitride nanotubes (RuB@BNNT and RuN@BNNT) for CO2RR are systematically investigated by density functional theory methods. The formation energy and dissolution potential are used to evaluate the stability of catalysts, and the results signify that RuB@BNNT and RuN@BNNT possess high thermodynamic and electrochemical stability. Based on Gibbs free energy calculation, RuB@BNNT and RuN@BNNT exhibit remarkably high catalytic performance to form methane (CH4) with extremely low limiting potentials of -0.58 and -0.32 V, respectively. In addition, electron structure analysis shows that RuB@BNNT and RuN@BNNT are considered as "electron sponges" during the CO2RR process. Especially, RuN@BNNT can significantly inhibit the competitive hydrogen evolution reaction (HER) with the limiting potential of -0.96 V, ensuring the smooth progress of CO2RR. This work will provide a guideline for the design of highly efficient CO2RR electrocatalysts.