Construction of multi-scale 1D/2D CdS/ZnS(en)0.5 nanorod/nanosheet heterojunction to boost photocatalytic hydrogen generation performance

Abstract

Heterojunction strategy, especially 1D/2D heterojunction, has shown great promise in developing efficient photocatalysts. Herein, a novel multi-scale 1D/2D heterojunction was designed and constructed by assembling ultrafine CdS nanorods on large-sized ZnS(en)0.5 nanosheets via a facile one-pot solvothermal method. This multi-scale 1D/2D heterojunction possesses high specific surface area, abundant active sites, close heterointerface contact and short carrier transport length, all of which contribute to catalytic activity. Furthermore, defects (S2− vacancy and unsaturated Zn2+) were introduced to the ZnS(en)0.5 crystal by a low temperature annealing treatment. These defects could efficiently capture photogenerated holes of CdS, thus restraining the internal recombination of electron-hole pairs. The integration of multi-scale heterojunction and defects result in a superior H2 generation rate of 9.44 mmol h−1 g−1, which is 39.3 times higher than that of single CdS nanorods. The CdS/ZnS(en)0.5 heterojunction also exhibited long-term stability in multiple photocatalytic cycles. This study provides new insight into the heterojunction design and can be extended to the construct of other robust 1D/2D heterojunction photocatalysts.