Mn doping improves the photocatalytic performance of CdS photocatalysts

Abstract

In recent years, CdS photocatalytic materials are known for their relatively narrow bandgap and high light-absorbing ability, which is favoured by a wide range of academics in the field of photocatalysis. However pure CdS photogenerated carriers are susceptible to complexation and photocorrosion, so the photocatalytic effect is not ideal. In order to improve the photocatalytic performance of CdS, to study the mechanisms of their modification, this thesis employs transition metal (Mn)-doped CdS to enhance its photocatalytic performance and improve photocorrosion. MnxCd1-xS in cubic sphalerite phase was prepared by hydrothermal method, the photocatalytic decolourisation of 50 mL of 10 mg/L MB by Mn0.2Cd0.8S at 240 min in the photocatalytic experiment was 90 %, with a reaction rate constant of 0.00982 min-1, 3.86 times that of the cubic sphalerite phase CdS. The reaction rate constant was 0.01102 min-1, which is 4.42 times greater than the hexagonal fibrous zinc ore phase CdS. The doping of Mn both led to an increase in the photocatalytic stability of CdS, the main active groups in the photocatalytic degradation of MB by MnxCd1-xS were all O2-·.