Construction of high-efficiency CoS@Nb2O5 heterojunctions accelerating charge transfer for boosting photocatalytic hydrogen evolution

The random movement and easy recombination of photoinduced charges lead to a low conversion efficiency for photocatalytic hydrogen evolution. The cocatalyst design is a promising route to address such problem through introducing an appropriate cocatalyst on the semiconductor photocatalysts to construct the high-efficiency heterojunctions. Herein, novel CoS/Nb2O5 heterojunctions were constructed via in-situ loading CoS cocatalyst on the surface of Nb2O5 nanosheets. Through the femtosecond-resolved transient absorption spectroscopy, the average lifetime of charge carriers for 10 wt% CoS/Nb2O5 (159.6 ps) is drastically shortened by contrast with that of Nb2O5 (5531.9 ps), strongly suggesting the rapid charge transfer from Nb2O5 to CoS. The significantly improved charge-transfer capacity contributes to a high photocatalytic hydrogen evolution rate of 355 umol/h, up to 17.5 times compared with pristine Nb2O5. This work would provide a new design platform in the construction of photocatalytic heterojunctions with high charge-transfer efficiency. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

In this study, novel CoS/Nb2O5 heterojunctions were constructed by loading CoS cocatalyst on the surface of Nb2O5 nanosheets, significantly improving the photocatalytic hydrogen evolution rate. Femtosecond-resolved transient absorption spectroscopy results showed that the charge carrier lifetime in the CoS/Nb2O5 heterojunctions was drastically shortened, indicating a rapid charge transfer process.