Unassisted selective solar hydrogen peroxide production by an oxidised buckypaper-integrated perovskite photocathode

Hydrogen peroxide (H₂O₂) is an eco-friendly oxidant and a promising energy source possessing comparable energy density to that of compressed H₂. The current H₂O₂ production strategies mostly depend on the anthraquinone oxidation process, which requires significant energy and numerous organic chemicals. Photocatalyst-based solar H₂O₂ production comprises single-step O₂ reduction to H₂O₂, which is a simple and eco-friendly method. However, the solar-to-H₂O₂ conversion efficiency is limited by the low performance of the inorganic semiconductor-based photoelectrodes and low selectivity and stability of the H₂O₂ production electrocatalyst. Herein, we demonstrate unassisted solar H₂O₂ production using an oxidised buckypaper as the H₂O₂ electrocatalyst combined with a high-performance inorganic-organic hybrid (perovskite) photocathode, without the need for additional bias or sacrificial agents. This integrated photoelectrode system shows 100% selectivity toward H₂O₂ and a solar-to-chemical conversion efficiency of ~1.463%.