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

Herein, we explore a general Cu2-x S 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, Ag₂ S, PbS, SnS), ternary compound (CuInS₂ , Znx Cd1-x S), and quaternary compound (single-atom platinum anchored Znx Cd1-x S; Znx Cd1-x S-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 Znx Cd1-x S-Pt₁ exhibited outstanding photocatalytic performance of CO₂ to CO, with the highest CO generation rate of 75.31 μmol h⁻¹ .