Crystal Water in Minerals Modulates Oxygen Activation for Hydrogen Peroxide Photosynthesis.

Sunlight-responsive minerals contribute significantly to biogeochemical cycles by activating oxygen (O₂) to generate reactive oxygen species (ROS). However, the role of crystal water, incorporated into minerals through hydration during rock cycles, in O₂ activation remains largely unexplored. Here, we construct tungstite models containing oxygen vacancies to elucidate the modulation of mineral-based ROS dynamics by the synergy between oxygen vacancy and crystal water. Crystal water promotes the protonation process of superoxide anion radicals to produce hydrogen peroxide (H₂O₂) and alleviates its decomposition. This mineral-based H₂O₂ photosynthesis system efficiently eliminates organic pollutants in a sequential light-dark reaction. Furthermore, this synergy effect can extend to other metal oxide minerals such as TiO₂, SnO₂, CuO, ZnO, and Bi₂O₃. Our results illuminate an overlooked pathway for modulating the protonation process by immobilized water in hydrous minerals, playing a crucial role in ROS storage and migration and pollutant dynamics in a natural environment throughout the day/night cycle.