Versatile Synthesis of Hollow Metal Sulfides via Reverse Cation Exchange Reactions for Photocatalytic CO2 Reduction

Herein, we explore a general Cu2−xS nanocube template‐assisted and reverse cation exchange‐mediated growth strategy for fabricating hollow multinary metal sulfide. Unlike the traditional cation exchange method controlled by the metal sulfide constant, the introduction of tri‐n‐butylphosphine (TBP) can reverse cation exchange to give a series of hollow metal sulfides. A variety of hollow multinary metal sulfide cubic nanostructures has been demonstrated while preserving anisotropic shapes to the as‐synthesized templates, including binary compounds (CdS, ZnS, Ag2S, PbS, SnS), ternary compound (CuInS2, ZnxCd1−xS), and quaternary compound (single‐atom platinum anchored ZnxCd1−xS; ZnxCd1−xS‐Pt1). Experimental and density functional theory (DFT) calculations show that the hollow metal sulfide semiconductors obtained could significantly improve the separation and migration of photogenerated electron‐hole pairs. Owing to the efficient charge transfer, the ZnxCd1−xS‐Pt1 exhibited outstanding photocatalytic performance of CO2 to CO, with the highest CO generation rate of 75.31 μmol h−1. A Cu2−xS nanocube template‐assisted route inspired by the hard soft acid base (HSAB) principle was employed for successfully synthesizing a family of hollow metal sulfide (CdS, ZnS, Ag2S, PbS, SnS, CuInS2, ZnxCd1−xS, ZnxCd1−xS‐Pt1) via cation exchange reaction.