Metal-organic framework as nanoreactors to co-incorporate carbon nanodots and CdS quantum dots into the pores for improved H2 evolution without noble-metal cocatalyst

Abstract

Avoiding the utilization of noble-metal cocatalyst and the aggregation of nano photocatalysts in the preparation and photocatalytic reaction are two important aspects in the area of photocatalytic H2 evolution. In this work, for the first time, CdS quantum dots and carbon nanodots (CDs) were successfully co-immobilized in the cages of MIL-101 by one-step double solvents method followed by heating treatment. The optimum photocatalytic H2-evolution rate of CD/CdS@MIL-101(50) composite with CDs content of 5.2 wt% exhibits a H2 evolution rate of 14.66 μmol h−1 without noble metal assisted under visible-light irradiation, which is 8.5 and 18.6 times higher than that of CdS@MIL-101 and bare CdS, respectively. The improved photocatalytic H2-production activity of CD/CdS@MIL-101 ternary composite is predominantly attributed to the effect of CDs, which mainly serves as an electron collector to efficiently prolong the lifetime of the photogenerated charge carriers from CdS@MIL-101 heterostructure. This work provide a new strategy of one-step double solvents method to co-incorporate two functional species to the pores of metal-organic frameworks (MOFs) to improve the photocatalytic H2 evolution activity of host photocatalyst.