Vacancy-engineered MoSe2/CdS hollow heterostructures boosting visible-light-induced Z-scheme photocatalysis

Abstract

Enhancing Z-scheme photocatalysis of hollow semiconductor heterostructures via controllable vacancy engineering is intriguing yet still under-developed to now. In this work, hollow MoSe2/CdS Z-scheme heterojunction was constructed by assembling S vacancies (SV)-engineered CdS hollow spheres with few-layer MoSe2 nanosheets, where Mo-S chemical bonds serve as the fast channel for Z-scheme charge transmission as validated by in-situ light-irradiated X-ray photoelectron spectroscopy (XPS), surface photovoltage spectroscopy (SPV), and •O2 -radicals production results. Intriguingly, the components' Fermi level (Ef) discrepancy of MoSe2/CdS heterojunction can be enlarged by SV content modulation, which helps to strengthen the internal electric field (IEF) to drive Z-scheme charge transmission efficiently. Meanwhile, the MoSe2/CdS could benefit from the enhanced light harvest and catalytic reaction kinetics by hollow architecture. Therefore, the MoSe2/CdS heterojunction displayed an exceptional visible-light-induced (λ > 400 nm) H2 evolution activity of 20.49 mmol•g -1 •h -1 , approximately 89.1 and 13.0 folds promotion than CdS and 3% Pt-CdS and it also exceeds that of many CdSbased photocatalysts reported previously. In addition, the MoSe2/CdS heterojunction also exhibited outstanding photocatalytic robustness for cyclic and long-term H2 production. The present study may shed new light on constructing highly-active photocatalysts through vacancy engineering of hollow structured Z-scheme heterojunction.