Atomic-Level Regulated Two-Dimensional ReSe 2 : A Universal Platform Boosting Photocatalysis.

Solar hydrogen (H 2 ) 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 we report atomic-level engineering of defected ReSe 2 nanosheets (NSs) to significantly boost photocatalytic H 2 evolution on various semiconductor photocatalysts including TiO 2 , CdS, ZnIn 2 S 4 and C 3 N 4 . 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 ReSe 2 /TiO 2 interface and substantial atomic-level active sites of defected ReSe 2 NSs result in the significantly raised activity of ReSe 2 /TiO 2 . Our work not only for the first time realizes the atomic-level engineering of ReSe 2 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 two dimensional materials for energy conversion and storage. This article is protected by copyright. All rights reserved.