A comparative study of the effects of different TiO supports toward CO electrochemical reduction on CuO/TiO electrode.

CuO-based electrodes possess vast potential in the field of CO electrochemical reduction. Meantime, TiO supports show the advantages of being non-toxic, low-cost and having high chemical stability, which render it an ideal electrocatalytic support with CuO. However, different morphologies and structures of TiO supports can be obtained through various methods, leading to the discrepant electrocatalytic properties of CuO/TiO. In this paper, three supports, named dense TiO, TiO nanotube and TiO nanofiber, were applied to synthesize CuO/TiO electrodes by thermal decomposition, and the performances of the electrocatalysts were studied. Results show that the main product of the three electrocatalysts was ethanol, but the electrochemical efficiency and reaction characteristics are obviously different. The liquid product of CuO/Dense TiO is pure ethanol, however, the current efficiency is rather low owing to the higher resistance of the TiO film. CuO/TiO nanotube shows high conductivity and ethanol can be synthesized at low overpotential with high current efficiency, but the gas products cannot be restricted. CuO/TiO nanofiber has a larger specific surface area and more active sites, which is beneficial for CO reduction, and the hydrogen evolution reaction can be evidently restricted. The yield of ethanol reaches up to 6.4 μmol cm at -1.1 V ( SCE) after 5 h.