Transition Metal\nPhosphides (Fe<sub>2</sub>P, Co<sub>2</sub>P, and Ni<sub>2</sub>P)\nModified CdS Nanorods for Efficient\nPhotocatalytic H<sub>2</sub> Evolution

As cocatalysts play important roles in enhancing the\ncatalytic\nperformance, designing and fabricating highly active cocatalysts is\nan effective approach to improving photocatalytic H<sub>2</sub> production.\nIn this work, transition metal phosphides (including Fe<sub>2</sub>P, Co<sub>2</sub>P, and Ni<sub>2</sub>P) with nanoscale structures\nare synthesized by the solvothermal method, which can largely enhance\nthe photocatalytic activity and stability of CdS nanorods as cocatalysts.\nBy optimizing the synthesis and reaction conditions, 10% Co<sub>2</sub>P/CdS achieved the highest H<sub>2</sub> production, about 29.24\nmmol·g<sup>–1</sup>·h<sup>–1</sup> in the\nlactic acid solution, which was 21.5 and 3.0 times higher than that\nof CdS (1.36 mmol·g<sup>–1</sup>·h<sup>–1</sup>) and 1% Pt/CdS (9.63 mmol·g<sup>–1</sup>·h<sup>–1</sup>), respectively. Testing by many characterizations,\nnot only the reasons for different activities for TMPs/CdS but also\nthe enhanced reasons of Co<sub>2</sub>P/CdS are explored. The results\nindicated that the non-noble metal Co<sub>2</sub>P cocatalyst not\nonly enhanced the visible light absorption of CdS but also promoted\nthe effective separation of photogenerated charge carriers. This work\ncontributes to the further development of TMPs as low-cost and highly\nactive cocatalysts for CdS-based photocatalysts.