Noble-metal-free MoS2 co-catalyst decorated UiO-66/CdS hybrids for efficient photocatalytic H2 production

Abstract

A novel and highly efficient photocatalyst MoS2/UiO-66/CdS has been fabricated through dual modification of CdS with metal-organic framework (MOF) UiO-66 and MoS2. UiO-66 was firstly introduced as a matrix for the well-dispersed growth of CdS, resulting in large active surface area. Moreover, the heterojunction between UiO-66 and CdS promoted the separation of photogenerated electron–hole pairs. MoS2 as cocatalyst was further deposited on UiO-66/CdS via a facile photo-assisted approach. This technique made CdS, UiO-66 and MoS2 undergo an intimate interfacial interaction, setting a stage for rapid transfer of photogenerated electrons between the components of the composite, and hence dramatically increased the synergetic catalytic effect of UiO-66, MoS2 and CdS. Without a noble-metal cocatalyst, the obtained MoS2/UiO-66/CdS composites functioned as high-performance photocatalysts for H2 evolution under visible light irradiation. An unusual H2 production rate of 650μmolh−1 has been reached by the sample of MoS2/UiO-66/CdS when the content of UiO-66 is 50wt% and MoS2 is 1.5wt%. This is nearly 60 times higher than the H2 evolution rate with pure CdS and also exceeds that of Pt/UiO-66/CdS under the same reaction conditions. More importantly, in sharp contrast with the obvious deterioration in photoactivity of pure CdS, the MoS2/UiO-66/CdS displayed significantly enhanced photostability. This study clearly demonstrates the benefit of using MOFs as ideal support and MoS2 as cocatalyst to work cooperatively for enhancing the photocatalytic H2 evolution activity and stability of semiconductors.