Continuous photocatalytic preparation of hydrogen peroxide with anthraquinone photosensitizers

Abstract

Hydrogen peroxide (H₂O₂) is a versatile oxidant, and its eco-friendly synthesis via visible light and air oxygen is crucial. Anthraquinone compounds were employed as homogeneous photocatalysts for alcohol oxidation, yielding H₂O₂ under visible light. Instead of using traditional catalyst library screening, a model based on density functional theory was proposed to structurally optimize anthraquinone photocatalysts, resulting in the discovery of a novel catalyst significantly boosting H₂O₂ generation (up to 621.2 mM h⁻¹ intermittently). Continuous flow reactor design improvements can enhance chemical transformation efficiency, as demonstrated by continuous H₂O₂ production using 2,6-di-tert-butyl anthraquinone. When isopropanol was used as the hydrogen atom donor, H₂O₂ production rates reached 3950.6 mM h⁻¹ in a 7-minute reaction, with a space–time yield of 7.90 mol (L h)⁻¹, showcasing promising advancements in green H₂O₂ synthesis.