Simultaneous increase of conductivity, active sites and structural strain by nitrogen injection for high-yield CO₂ electro-hydrogenation to liquid fuel

Electrocatalytic hydrogenation of CO₂ has become particularly promising to address the grand issues of global warming and energy crisis. Herein, we report simultaneous increase of conductivity, active sites and structural strain of copper selenide nanosheets by nitrogen (N)-injection (N-CuSe), resulting in significant improvement in CO₂ electroreduction. At the applied potential of −1.1 V vs. reversible hydrogen electrode in CO₂-saturated 0.5 mol L^–1 KHCO₃, the N-CuSe delivers a current density of ∼46.7 mA cm^–2, 3.1-folds as that of the pristine CuSe. A high production yield of liquid products containing formate (~22.1 mg h⁻¹ cm⁻²), acetate (~1.2 mg h⁻¹ cm⁻²) and ethanol (~1.0 mg h⁻¹ cm⁻²) is achieved by N-CuSe, which is over 11-folds as that produced by the pristine CuSe. Such a facile strategy simultaneously enhancing conductivity, active sites and structural strain holds great promise on promoting catalysts for a big variety of reactions, not limited to CO₂ electroreduction.