Roughened TiO2 film electrodes for electrocatalytic reduction of oxalic acid to glyoxylic acid

• Roughened TiO2 film electrode was prepared by anodic oxidation method.
• Roughened TiO2 film electrode was used to investigate the electrocatalytic reduction of oxalic acid.
• The electrocatalytic properties were studied using CV, in situ FTIR and preparative electrolysis experiments.
• Mechanism of electrocatalytic reduction of oxalic acid at the roughened TiO2 film electrode was proposed.

Roughened TiO2 film electrodes were prepared by anodic oxidation method in 1.0 M sulfuric acid solution. The prepared electrode and the electrode after electrolysis were characterized by XPS and SEM. It was observed that the roughened surface disappeared and 0.5–1 μm holes formed after electrolysis. While TiO2 film always existed on the surface of the anodized electrode. The adsorption and reduction of oxalic acid at the prepared electrode likely benefited from this porous structure. The electrocatalytic properties of the roughened TiO2 film electrode towards the electrocatalytic reduction of oxalic acid to glyoxylic acid were evaluated by CV, in situ FTIR and preparative electrolysis experiments. Experimental evidence was presented that the roughened TiO2 film electrode exhibited higher electrocatalytic activity for the reduction of oxalic acid. In addition, a new mechanism of the electrocatalytic reduction of oxalic acid was proposed, in which TiO2/Ti(OH)3 redox couple plays an important role in the reduction of oxalic acid.