Desert rose-like zinc-doped copper sulfide: a promising photoelectrode for efficient solar water splitting
摘要
In this study, pristine copper sulfide (CS) and zinc-doped copper sulfide (CSZ) photoelectrodes were successfully synthesized using a simple and cost-effective hydrothermal method. The prepared materials exhibited a distinctive three-dimensional(3D) desert rose-like morphology composed of hierarchical nanosheet assemblies, as confirmed by XRD, SEM, and TEM analyses. This unique architecture provides a large active surface area, improved light harvesting, and favorable pathways for charge transport. Compared with pristine CS, Zn-doped CS showed significantly enhanced photoelectrochemical (PEC) water oxidation performance. The optimized CSZ photoelectrode achieved a photocurrent density of 2.27 mA cm− 2 at 1.5 V vs. Ag/AgCl, which is 1.62 times higher than that of pristine CS (1.40 mA cm− 2), along with a lower onset potential of 0.694 V, indicating improved reaction kinetics. Transient photocurrent measurements further revealed a faster photo response and enhanced stability for CSZ, reaching 0.60 mA cm− 2 compared with 0.39 mA cm− 2 for CS. The applied bias photon-to-current efficiency of CSZ reached 0.10%, exceeding that of pristine CS (0.038%). The enhanced performance is attributed to the synergistic effect of Zn incorporation and the desert rose-like structure. Zn2+ ions are proposed to partially substitute Cu sites, forming stronger Zn–S interactions due to their stable closed-shell 3d10 electronic configuration, thereby reducing unstable copper-related defect sites, suppressing lattice distortion, and improving charge transport under PEC conditions. These results demonstrate that CSZ is a promising photoelectrode material for efficient and stable PEC water splitting applications.