Phase-Controlled Synthesis of Single-Crystalline Tin Sulfide Nanosheets for PEC Water Oxidation

Precise control over the stoichiometry and phase of tin sulfide (SnS_x) nanomaterials is critical for their potential applications in energy conversion and storage devices, which remains challenging. Here, we report a precursor-mediated colloidal method to achieve phase-controlled synthesis of single-crystalline (SC) SnS_x nanosheets. By employing Sn(acac)₂Cl₂/S and SnCl₂·2H₂O/1-DDT as precursors, hexagonal SC SnS₂ nanosheets and orthorhombic SC SnS nanosheets were successfully synthesized, respectively. The photoelectrochemical (PEC) performance of both samples as photoanodes for water oxidation was further studied. The SC SnS₂ nanosheet photoanode achieves a PEC performance of 1500 μA cm^-2 at 1.23 V_RHE with a half-cell solar-to-hydrogen conversion efficiency of 0.85%, outperforming the SC SnS nanosheet photoanodes. Meanwhile, this precursor-mediated method can be readily extended to the phase- and stoichiometry-controlled synthesis of other 2D nanomaterials, which hold great potential in photocatalysis and photoelectrochemical applications.