An Unusual Strong Visible‐Light Absorption Band in Red Anatase TiO2 Photocatalyst Induced by Atomic Hydrogen‐Occupied Oxygen Vacancies

by intentionally introducing atomic hydrogen-mediated oxygen vacancies. Combining experimental characterizations with theoretical calculations reveals the excitation of a new subvalence band associated with atomic hydrogen filled oxygen vacancies as the origin of such band, which subsequently leads to active photo-electrochemical water oxidation under visible light. These findings could provide a powerful way of tailoring wide-bandgap semiconductors to fully capture solar light.