Atomic‐Level Regulated 2D ReSe₂: A Universal Platform Boostin Photocatalysis

Solar hydrogen (H₂ ) generation via photocatalytic water splitting is practically promising, environmentally benign, and sustainably carbon neutral. It is important therefore to understand how to controllably engineer photocatalysts at the atomic level. In this work, atomic-level engineering of defected ReSe₂ nanosheets (NSs) is reported to significantly boost photocatalytic H₂ evolution on various semiconductor photocatalysts including TiO₂ , CdS, ZnIn₂ S₄ , and C₃ N₄ . Advanced characterizations, such as atomic-resolution aberration-corrected scanning transmission electron microscopy (AC-STEM), synchrotron-based X-ray absorption near edge structure (XANES), in situ X-ray photoelectron spectroscopy (XPS), transient-state surface photovoltage (SPV) spectroscopy, and transient-state photoluminescence (PL) spectroscopy, together with theoretical computations confirm that the strongly coupled ReSe₂ /TiO₂ interface and substantial atomic-level active sites of defected ReSe₂ NSs result in the significantly raised activity of ReSe₂ /TiO₂ . This work not only for the first time realizes the atomic-level engineering of ReSe₂ NSs as a versatile platform to significantly raise the activities on different photocatalysts, but, more importantly, underscores the immense importance of atomic-level synthesis and exploration on 2D materials for energy conversion and storage.