Photocatalytic Hydrogen Peroxide Production with an External Quantum Yield of Almost 500%

Abstract

From the perspective of energy and environmental issues, the development of green methods for H₂O₂ production is demanded as an alternative to the conventional energy-intensive anthraquinone method. Among the candidates, photocatalytic H₂O₂ production has recently attracted much interest. To withstand the use under harsh conditions, it is desirable that the photocatalyst be composed of robust inorganic materials. However, the external quantum yield (ϕ_ex) of H₂O₂ production by inorganic photocatalysts remains below 20% in most studies. Here we demonstrate that a nanohybrid photocatalyst consisting of antimony-doped SnO₂ and ZnO can produce H₂O₂ with a ϕ_ex of ~500% from O₂-saturated ethanol aqueous solution under UV-light irradiation. In the photochemical reactions, the quantum yield is usually far below unity (< 100%) due to the rapid recombination of photogenerated charge carriers. Breaking through this limit will pave the way for innovative photochemical reactions with the photocatalytic H₂O₂ synthesis brought closer to practical application.