Rational Photodeposition of Cobalt Phosphate on Flower-like ZnIn₂S₄ for Efficient Photocatalytic Hydrogen Evolution

The high electrons and holes recombination rate of ZnIn₂S₄ significantly limits its photocatalytic performance. Herein, a simple in situ photodeposition strategy is adopted to introduce the cocatalyst cobalt phosphate (Co-Pi) on ZnIn₂S₄, aiming at facilitating the separation of electron-hole by promoting the transfer of photogenerated holes of ZnIn₂S₄. The study reveals that the composite catalyst has superior photocatalytic performance than blank ZnIn₂S₄. In particular, ZnIn₂S₄ loaded with 5% Co-Pi (ZnIn₂S₄/5%Co-Pi) has the best photocatalytic activity, and the H₂ production rate reaches 3593 μmol·g^-1·h^-1, approximately double that of ZnIn₂S₄ alone. Subsequent characterization data demonstrate that the introduction of the cocatalyst Co-Pi facilitates the transfer of ZnIn₂S₄ holes, thus improving the efficiency of photogenerated carrier separation. This investigation focuses on the rational utilization of high-content and rich cocatalysts on earth to design low-cost and efficient composite catalysts to achieve sustainable photocatalytic hydrogen evolution.