CO₂ Conversion with Light and Water by GaN Photoelectrode

Abstract

Light illumination on a photoelectrode creates separate electron and hole pairs that lead to an oxidation and reduction reaction. Here, we show that CO 2 reduction by means of water and light is realized by a gallium nitride (GaN) photoelectrode in which excited electrons drive CO 2 conversion at the counterelectrode. A copper (Cu) plate was chosen as the counterelectrode. With this system, the generation of formic acid (HCOOH) with 9% Faradic efficiency was confirmed by light illumination alone with the help of NiO co-catalysts.