Self‐powered Photoelectrochemical Sensor for Gallic Acid Exploiting a CdSe/ZnS Core‐shell Quantum Dot Sensitized TiO₂ as Photoanode

Abstract

Abstract Herein is described the development of a self‐powered sensor for gallic acid (GA) determination exploiting CdSe/ZnS quantum dot sensitized TiO 2 nanoparticles (CdSe/ZnS/TiO 2 /FTO) as photoanode and an all copper oxide photocathode (CuO/Cu 2 O/FTO) to reduce water. A two‐chamber self‐powered photoelectrochemical cell was employed in order to maintain separated the photoelectrodes. The self‐powered photoelectrochemical cell is based on water reduction in the cathodic chamber while gallic acid acts as a hole scavenger in the anodic chamber to generate the necessary cell output to drive GA oxidation in the anodic compartment. Electrochemical impedance measurements were performed to evaluate the electronic characteristics of CdSe/ZnS/TiO 2 /FTO photoanode and CuO/Cu 2 O/FTO photocathode in terms of flat band potential, carrier density, and nature of semiconductor. Under optimized conditions, the self‐powered photoelectrochemical cell presented a wide linear response range for GA from 1 μmol L −1 up to 200 μmol L −1 .