Surface Hydroxylated S/O Dual‐Vacancy S‐Scheme Hollow [In2S3‐x/In2O3‐x](OH)y Heterojunction for Photothermal‐promoted Low‐Temperature Methanol/Water Reforming into Hydrogen

To enable highly efficient in situ hydrogen release from methanol/water reforming at lower temperature, the integration of solar‐energy offers a promising approach to activate methanol/water and substantially lower the activation energy of this reaction. Herein, we present a novel dual‐vacancy defective hollow heterostructure derived from Metal‐Organic Frameworks, featuring abundant surface hydroxyl groups and S/O vacancies, for photothermal‐promoted methanol solution reforming into hydrogen. The [In2S3‐x/In2O3‐x](OH)y exhibits exceptional photothermal H2 evolution activity, achieving a production rate of 215.2 mmolgcat‐1h‐1, 16‐fold higher than its thermocatalytic activity, with an apparent quantum efficiency of 66.8% and solar‐to‐hydrogen efficiency of 6.5% at 365 nm and excellent durability over 82 h, cumulating 2.61×103 mmolgcat‐1. The synergistic effects of dual‐vacancies and the hollow heterostructure significantly enhance the photothermal effect, lowering the activation energy barrier for methanol/water, enabling H2 production at temperatures even as 80 °C under non‐alkaline conditions. Furthermore, the incorporated surface hydroxyl groups facilitate the generation of active surface hydroxyls from water, further driving activation and cleavage of C‐H bonds in methanol, thereby markedly reducing the apparent reaction activation energy by 12.5 %. This work provides a new strategy for effective H2 production from aqueous methanol reforming under mild conditions, holding great promise for energy‐demanding industrial applications.