Prolonged electron lifetime in sulfur vacancy-rich ZnCdS nanocages by interstitial phosphorus doping for photocatalytic water reduction

Abstract

Hollow metal sulfides have been extensively investigated as photocatalysts for the hydrogen evolution reaction (HER) due to their enhanced light harvesting ability and sufficient catalytic sites. However, their HER performance is still limited owing to the unavoidably photogenerated charge carrier recombination. Herein, we design a sulfur vacancy-rich ZnCdS nanocage photocatalyst with interstitial phosphorus doping (P-ZnCdS) by using zeolitic-imidazolate-framework-8 (ZIF-8) rhombic dodecahedrons as the template. Interstitial P doping endows P-ZnCdS with a promoted Fermi level, which shortens the distance between the Fermi level and S vacancy level, thus facilitating the S vacancy level to be an effective electron trapping center and improving the separation efficiency of electron–hole pairs. As expected, the HER performance of the P-ZnCdS nanocages is dramatically enhanced to nearly 57.21 μmol h⁻¹ when compared to that of pristine ZnCdS nanocages (21.58 μmol h⁻¹). This work underscores the way to design high-performance photocatalysts using the interstitial P doping strategy.