Facilitated series electrochemical hydrogenation of oxalic acid to glycolic acid using TiO2 nanotubes

In this study, the electrochemical reduction of oxalic acid (OX) was performed at electrodes made of TiO2 nanotubes (TNTs) in an aqueous medium under potentiostatic control in a two-compartment cell. The competing H-2 evolution was almost non-existent at an applied potential of 1.0 V vs Ag/AgCl. Thus, complete conversion of OX was achieved in high chemical (95%) and Faradaic (67%) yields. The selectivity of glycolic acid (GC) formation over that of glyoxylic acid (GO) is controlled by the length of the TNTs. A high selectivity (GC/GO approximate to 10) was obtained (glycolic acid/glyoxylic acid approximate to 10). The physical properties of the TNTs, such as length, uniformity, and mechanical strength, were controlled by varying the anodization time and the electrolyte composition.

Automated summary

In this study, the electrochemical reduction of oxalic acid was efficiently achieved using TiO2 nanotubes as electrodes. Complete conversion of oxalic acid and high selectivity of glycolic acid formation were achieved by controlling the length of the nanotubes.