ZnSe/Ta2O5 heterojunction with high carrier separation efficiency: Experimental and theoretical calculations

Abstract

Herein, we synthesized ZnSe nanoparticles by hydrothermal method, and confirmed that constructing ZnSe/Ta2O5 heterojunction structure can effectively solve the problem of too short photo-generated carrier lifetime of ZnSe, thereby improving the photocatalytic performance of the material. The band gaps of the prepared ZnSe nanoparticles and Ta2O5 nanosheets are 2.56 eV and 3.54 eV, respectively. When their mass ratio is 5:1, the ZnSe/Ta2O5 photocatalyst with the best photocatalytic performance can be prepared, and its photocatalytic degradation rate of RhB is 7.2 times of ZnSe nanoparticles and 11 times of Ta2O5 nanosheets. In addition, the photocatalytic hydrogen evolution rate of ZnSe/Ta2O5 photocatalyst can reach 1.264 mmol·g−1·h−1, which is 1.7 times that of ZnSe nanoparticles and 4.4 times of Ta2O5 nanosheets. Both characterization and theoretical calculations confirmed that there is a strong electron transfer at the interface between ZnSe and Ta2O5, which makes the oxygen atoms in Ta2O5 obtain abundant electrons, effectively forming electron transport tunnels, and ultimately accelerating the separation of photogenerated carriers. In addition, the energy band structure of the material and the active species in the reaction process are analyzed, and the photocatalytic reaction mechanism of the ZnSe/Ta2O5 photocatalyst is proposed in detail. This work is significance for broadening the practical application scenarios of ZnSe in the field of photocatalysis.