Thermal-assisted synthesis of unique Cu nanodendrites for the efficient electrochemical reduction of CO2

[Display omitted] •Direct growth of unique Cu nanodendrites via a facile thermal treatment.•The formed Cu nanodendrites exhibit excellent activity for CO2 reduction.•The kinetics of CO2 reduction was probed by in situ FTIR technique.•Formation of CO, CH4, HCOO−, CH3COO−and CH3OH at a low overpotential.•Superb current efficiency (82%) was achieved at −0.4 V. Herein, we report on novel Cu nanodendrites, which were formed when the electrodeposited Cu thin film on a Ti substrate was thermally treated in the presence of a mixture of CuSO4 and H2SO4. The formed Cu nanodendrites exhibit superior catalytic activity for the electrochemical reduction of CO2, showing that the unique nanostructure and the large electrochemically active surface area play critical roles in the efficient electrochemical reduction of CO2. Gas chromatography and NMR spectroscopy were employed to identify the products of the CO2 reduction, confirming the formation of CO, CH4, HCOO−, CH3COO− and CH3OH. The kinetics of the CO2 reduction was further investigated using in situ electrochemical ATR-FTIR spectroscopy. The facile approach to the fabrication of the unique Cu nanodendrites, the superior catalytic activity, and the high current efficiency make the Cu nanodendrites as a promising electrocatalyst for the effective electrochemical reduction of CO2 to valuable products.