Surface photosensitization of ZnO by ZnS to enhance the photodegradation efficiency for organic pollutants

Abstract It is challenging to develop a material which has low cost, high activity, good stability and recyclability under light exposure. Apart from these properties, the photocatalyst should also have good visible region absorbance and low electron-hole pair recombination rate. Keeping all this in view, we have designed a simple scalable synthesis of ZnO–ZnS heterostructures for the photocatalytic treatment of industrial waste (p-nitrophenol and methyl orange). The ZnO–ZnS heterostructures are synthesized via a solvent-free route by thermal annealing of solid-state mixture of ZnO and thiourea (a sulphur source) which results in ZnO–ZnS core shell kind of heterostructure formation. The interface formation between the ZnO–ZnS heterostructure favored the band-gap reduction in comparison to the bare ZnO and ZnS nanoparticles. Further, these ZnO–ZnS heterostructures were utilized as a photocatalyst for the degradation of toxic phenolic molecules (p-nitrophenol) and harmful organic dyes (methyl orange) present in the water under the light exposure (> 390 nm)