Surface photosensitization of ZnO by ZnS to enhance the photodegradation efficiency for organic pollutants
Sunaina Sunaina, Sapna Devi, S.T. Nishanthi, S.K. Mehta, Ashok K. Ganguli, Menaka Jha
Abstract
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).