WSe-loaded co-catalysts CuP and CNTs: Improving photocatalytic hydrogen precipitation and photocatalytic memory performance.

Photocatalytic decomposition of water for hydrogen production using semiconductor photocatalysts in visible light is considered one of the most promising environmentally friendly ways to produce hydrogen. In this work, the calcination method was adopted to prepare an efficient CuP/WSe/CNTs composite photocatalysts. CuP and carbon nanotubes (CNTs) were used as co-catalysts to reduce the composite rate of the photogenerated supports of the photocatalyst. The unique metallic properties of CuP as a transition metal phosphide makes it a cost-effective alternative to noble metal co-catalysts. CNTs can serve both as co-catalysts and as a suitable carrier to accelerate the transfer rate of photogenerated electrons. The experimental results showed that the CuP/WSe/CNTs composite photocatalyst exhibited stronger activities in photocatalytic hydrogen production than pure WSe. In particular, a higher quantum yield of 30.27% at the range 400-700 nm was achieved with a loading of 4% CNTs, a calcination temperature of 300 °C and a calcination time of 2.0 h. In contrast, the quantum yield of pure WSe was only 14.01%. The highest hydrogen production rate was 6.987 mL in 4.0 h, and the average hydrogen production rate was 712.985 μmol·hg, which was 2.39 times higher than that of pure WSe.The catalytic memory performance of the composite samples was also examined. The results indicated that the best catalytic memory performance was achieved under the pre-illumination condition of 5.0 h. The amount of hydrogen produced under darkness for 4.0 h was up to 4.934 mL and the average hydrogen production rate was 503.454 μmol·hg. The average hydrogen production rate was 1.69 times higher than the average hydrogen production rate of pure WSe under light conditions.