Green hydrogen evolution from semi-dissolved water adopting narrow band gap WSe 2 /Cu 3 P (WP) composite photocatalyst

Herein, Cu 3 P was used as a co-catalyst to improve the separation efficiency of photogenerated carriers in WSe 2 photocatalysts. The metallic nature of Cu 3 P and its noble metal-like properties make it an affordable and efficient co-catalyst. The experimental results revealed that the photocatalytic activity of the WSe 2 /Cu 3 P (WP) sample was significantly higher under visible light with an average hydrogen evolution rate (HER) of 616.50 μmol h −1 g −1 and a quantum yield of 23.75%. In contrast, the average HER of the pure WSe 2 sample was only 298.46 μmol h −1 g −1 . The preparation parameters were optimized by a single-factor test. The optimal preparation parameters were as follows. The loading of Cu 3 P was 8%, and the calcination time and temperature were 2.0 h and 300 °C, respectively. An innovative exploration of the photocatalytic memory effect of WP photocatalyst was carried out. The analysis of the experimental results displayed that the HER of the WP photocatalyst under dark conditions reached 418.50 μmol h −1 g −1 after 5.0 h post-illumination. Graphical abstract