Microwave-assisted synthesis of ZnxCd1−xS–MWCNT heterostructures and their photocatalytic properties

The multi-walled carbon nanotubes (MWCNTs) wrapped with hexagonal wurtzite ZnxCd1−xS nanoparticles with a uniform and small diameter have been prepared to form ZnxCd1−xS–MWCNT heterostructures by microwave-assisted route using Zn(Ac)2, Cd(NO3)2, and thioacetamide as the reactants. The heterostructures have been characterized by X-ray powder diffraction, scanning and transmission electron microscopy, high-resolution transmission electron microscopy, photoluminescence (PL) and PL excited lifetime. Despite the analogous size and configuration, the ZnxCd1−xS–MWCNT (x = 0, 0.2, 0.5, 0.8, 1) with different Zn concentration exhibit composition-dependent absorption properties in the visible zone. The PL peak positions of ZnxCd1−xS–MWCNT change gradually from ZnS–MWCNT to CdS–MWCNT. The ZnxCd1−xS–MWCNT shows different photocatalytic activity towards the photodegradation of fuchsin acid under visible light illumination, photocatalytic activity of the ZnxCd1−xS–MWCNT decreases gradually with the increase in the Zn concentration, the Zn0.2Cd0.8S–MWCNT possessed the best photocatalytic activity. After recycling thrice, the photocatalysts still have about 85% efficiency.