Transition Metal Phosphides (Fe2P, Co2P, and Ni2P) Modified CdS Nanorods for Efficient Photocatalytic H2 Evolution

As cocatalysts play important roles in enhancing the catalytic performance, designing and fabricating highly active cocatalysts is an effective approach to improving photocatalytic H₂ production. In this work, transition metal phosphides (including Fe₂P, Co₂P, and Ni₂P) with nanoscale structures are synthesized by the solvothermal method, which can largely enhance the photocatalytic activity and stability of CdS nanorods as cocatalysts. By optimizing the synthesis and reaction conditions, 10% Co₂P/CdS achieved the highest H₂ production, about 29.24 mmol·g^–1·h^–1 in the lactic acid solution, which was 21.5 and 3.0 times higher than that of CdS (1.36 mmol·g^–1·h^–1) and 1% Pt/CdS (9.63 mmol·g^–1·h^–1), respectively. Testing by many characterizations, not only the reasons for different activities for TMPs/CdS but also the enhanced reasons of Co₂P/CdS are explored. The results indicated that the non-noble metal Co₂P cocatalyst not only enhanced the visible light absorption of CdS but also promoted the effective separation of photogenerated charge carriers. This work contributes to the further development of TMPs as low-cost and highly active cocatalysts for CdS-based photocatalysts.