One‐Step Solid‐Phase Synthesis of 2D Ultrathin CdS Nanosheets for Enhanced Visible‐Light Photocatalytic Hydrogen Evolution

Photocatalysts with 2D ultrathin nanosheet structures are gradually attracting significant interest from researchers because of their excellent photoelectric and physicochemical properties. However, the efficient fabrication of 2D CdS nanosheets with high crystallinity and ultrathin thickness still faces huge challenges. In this work, 2D ultrathin CdS nanosheets are synthesized through a simple one‐step solid‐phase strategy using CdSO 4 · 8/3H 2 O as precursors in the CH 4 N 2 S atmosphere. The 2D ultrathin CdS nanosheet obtained by calcining at 300 °C for 4 h shows superior photocatalytic activity: the photocatalytic rate of hydrogen generation reaches 149.67 μmol h −1 , and the corresponding apparent quantum efficiency is 36.7% at 450 nm. The enhanced photocatalytic activity and excellent photocatalytic stability are realized through the high crystallinity and ultrathin 2D nanosheet structure of CdS, which provide a high surface‐to‐volume ratio and enriched active adsorption sites. The 2D ultrathin nanosheet structure prevents the surface sulfide ions from being oxidized because of the extremely short interface distances and photocatalytic carrier transport, resulting in effective photocorrosion inhibition. Controlled experiments also show that the precursors ZnSO 4 · 7H 2 O and Cd(Ac) 2 · 2H 2 O are converted to 2D ZnS and CdS nanosheets through the one‐step solid‐phase method, illustrating that this simple one‐step solid‐phase strategy can be extended to the fabrication of other metal sulfide photocatalysts with 2D nanostructures.