Sustainable photocatalytic hydrogen peroxide production over octonary high-entropy oxide

The direct utilization of solar energy for the artificial photosynthesis of hydrogen peroxide (H₂O₂) provides a reliable approach for producing this high-value green oxidant. Here we report on the utility of high-entropy oxide (HEO) semiconductor as an all-in-one photocatalyst for visible light-driven H₂O₂ production directly from H₂O and atmospheric O₂ without the need of any additional cocatalysts or sacrificial agents. This high-entropy photocatalyst contains eight earth-abundant metal elements (Ti/V/Cr/Nb/Mo/W/Al/Cu) homogeneously arranged within a single rutile phase, and the intrinsic chemical complexity along with the presence of a high density of oxygen vacancies endow high-entropy photocatalyst with distinct broadband light harvesting capability. An efficient H₂O₂ production rate with an apparent quantum yield of 38.8% at 550 nm can be achieved. The high-entropy photocatalyst can be readily assembled into floating artificial leaves for sustained on-site production of H₂O₂ from open water resources under natural sunlight irradiation.