Catalysis of semiconductor nanoparticles towards electro-oxidation of ascorbic acid

Nano-materials show great electrocatalysis on redox reaction, e.g. metal nano-particles and carbon nano-tube. The electrocatalytic activity of semiconductor nano-particles, however, has not been reported although semiconductor was widely used as an electrode substrate for a variety of applications. In this work, we demonstrated a remarkable catalysis on electro-oxidation of ascorbic acid on indium tin oxide nano-particles (ITO NPs)-modified electrode. It was found that the oxidation potential of ascorbic acid decreased by ~800 mV, compared with that on sputtered ITO film electrode. Coupling with X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) emission studies, the catalytic effect can be deduced to relate with the existence of oxygen vacancy defects in In₂O₃ crystals, one of the components of ITO. The findings could shed light on fabricating novel electrochemical device for biosensing in future work.