Crystal\nWater in Minerals Modulates Oxygen Activation\nfor Hydrogen Peroxide Photosynthesis

Sunlight-responsive minerals contribute\nsignificantly to biogeochemical\ncycles by activating oxygen (O<sub>2</sub>) to generate reactive oxygen\nspecies (ROS). However, the role of crystal water, incorporated into\nminerals through hydration during rock cycles, in O<sub>2</sub> activation\nremains largely unexplored. Here, we construct tungstite models containing\noxygen vacancies to elucidate the modulation of mineral-based ROS\ndynamics by the synergy between oxygen vacancy and crystal water.\nCrystal water promotes the protonation process of superoxide anion\nradicals to produce hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>)\nand alleviates its decomposition. This mineral-based H<sub>2</sub>O<sub>2</sub> photosynthesis system efficiently eliminates organic\npollutants in a sequential light–dark reaction. Furthermore,\nthis synergy effect can extend to other metal oxide minerals such\nas TiO<sub>2</sub>, SnO<sub>2</sub>, CuO, ZnO, and Bi<sub>2</sub>O<sub>3</sub>. Our results illuminate an overlooked pathway for modulating\nthe protonation process by immobilized water in hydrous minerals,\nplaying a crucial role in ROS storage and migration and pollutant\ndynamics in a natural environment throughout the day/night cycle.