Mn0.2Cd0.8S nanorods assembled with 0D CoWO4 nanoparticles formed p-n heterojunction for efficient photocatalytic hydrogen evolution

Abstract

In this work, p-type semiconductor CoWO4 nanoparticles was successfully anchored on the surface of n-type Mn0.2Cd0.8S nanorods, and p-n type heterostructure photocatalysts with low cost and high efficiency were synthesized. By optimizing the loading of CoWO4 nanoparticles, the hydrogen evolution rate of the compound can reach a maximum, the peak is 408 μmol/5 h. Under visible light irradiation, it is equivalent to 3.61 times pure Mn0.2Cd0.8S. In addition, the composite catalyst has favorable durability and structural stability. In terms of morphology, the combination of nanorods (SBET = 24 m2g-1) and nanoparticles (SBET = 12 m2g-1) increased the specific surface area of the composite catalyst (SBET = 31 m2g-1), thus the composite exposed more active sites. In terms of heterojunction, the conduction bands of two semiconductors were determined by UV–vis diffuse reflection and Mott-Schottky, and the construction of p-n heterojunction was verified. The results of photochemical experiment further indicate that the built-in electric field in the p-n type heterostructure not only accelerates the electron-hole pair transfer, but vastly enhances the carrier average lifetime. In this paper, the morphology of the photocatalyst was modified and p-n heterojunction was constructed. The result is that the performance of Mn0.2Cd0.8S MCS was improved and the possible mechanism of photocatalytic hydrogen evolution was proposed.