Fabrication of novel Mn0.43Cd0.57S/ZnCo2O4 p-n heterojunction photocatalyst with efficient charge separation for highly enhanced visible-light-driven hydrogen evolution

Abstract

The construction of efficient and low-cost photocatalytic systems is a major challenge in the field of photocatalysis. An efficient heterojunction photocatalyst designed for water splitting is also an interesting prospect in energy conversion. In this study, a novel Mn0.43Cd0.57S/ZnCo2O4 p-n heterojunction photocatalyst was prepared via a simple solvothermal method. Mn0.43Cd0.57S was loaded on the surface the of noble metal-free transition metal oxide ZnCo2O4 to prevent the agglomeration of particles, resulting in efficiently improving the photocatalytic performance of the material. Due to the Fermi level balance, the band bending of the two materials constructs a p-n heterojunction, which stimulates the transfer of photogenerated electrons from the CB of Mn0.43Cd0.57S to the CB of ZnCo2O4. The uniformly dispersed p-n heterojunction structure effectively suppresses the recombination of photoinduced charges and preserves stronger redox charges. As a result, the established Mn0.43Cd0.57S/ZnCo2O4 heterojunction showed the best photocatalytic hydrogen production concentration (92.1 mmol g−1 h−1), which was 4.7 times that of the original Mn0.43Cd0.57S (19.4 mmol g−1 h−1) and 54.2 times that of ZnCo2O4 (1.7 mmol g−1 h−1). This strategy will provide new insights into the development of new photocatalysts.