Directing Mn_0.2Cd_0.8S/Co₃O₄ np Junctions for Highly Efficient Visible Light Hydrogen Production

The conversion of solar energy into hydrogen (H 2 ) through photocatalysis technology has been considered to be one of the most promising ways to alleviate the energy crisis. However, achieving efficient H 2 production is still a big challenge due to the rapid recombination of photogenerated carriers. In this work, we direct Mn 0.2 Cd 0.8 S/Co 3 O 4 np junctions via in situ growing p-type Co 3 O 4 nanoparticles on the surface of n-type Mn 0.2 Cd 0.8 S nanorods for photocatalytic hydrogen production. Compared to ex-situ-grown samples, the in-situ-grown samples construct many more channels for photogenerated charge carrier transfer via the np junctions and built-in electric field to promote their separation and migration, leading to enhanced photocatalytic hydrogen production. The results show that Mn 0.2 Cd 0.8 S/Co 3 O 4 -20 exhibits a H 2 production rate of 26.98 mmol h –1 g –1 under visible light, which is about 2.71 times higher than that of pure Mn 0.2 Cd 0.8 S. In addition, the apparent quantum efficiency at 450 nm of Mn 0.2 Cd 0.8 S/Co 3 O 4 -20 reaches 14.0%. Our work here provides insights into constructing heterojunctions to facilitate photogenerated charge separation and transfer for photocatalysis and photovoltaic applications.