Immobilizing CdS nanoparticles and MoS2/RGO on Zr-based metal–organic framework 12-tungstosilicate@UiO-67 toward enhanced photocatalytic H2 evolution

Abstract

The robust UiO-67 framework was selected as a platform to incorporate 12-tungstosilicic acid (SiW₁₂). The LUMO potential of the resulting SiW₁₂@UiO-67 is observed to be −0.29 V versus NHE and the HOMO potential can be calculated to be 3.21 V vs. NHE. The SiW₁₂@UiO-67 was firstly used as a supporting matrix to support the CdS nanoparticles and MoS₂/reduced graphene oxide (M/G) cocatalyst. The obtained composite SiW₁₂@UiO-67/M/G–CdS showed improved photocatalytic H₂ evolution activity. The optimum H₂ production over SiW₁₂@UiO-67/M/G–CdS can be obtained when 30 wt% SiW₁₂@UiO-67 is introduced in the composites, reaching 1.27 mmol h⁻¹ in the presence of 5% M/G, which is about 2 times that of M/G–CdS. The enhanced photocatalytic activity might be attributed to the large specific surface area of SiW₁₂@UiO-67 and the effective heterostructure between SiW₁₂@UiO-67 and CdS. In addition, the insertion of SiW₁₂ into the porous UiO-67 could improve its ability to transfer electrons. Therefore, the separation of photogenerated electrons and holes could be accelerated and the fast recombination of charge carriers of CdS could be suppressed.