Enhancement of visible light photocatalytic activity of ZnS and CdS nanoparticles based on organic and inorganic coating

Abstract

Coating of ZnS and CdS nanoparticles with organic and inorganic materials can extend their light absorption in the visible region and their stability against photo-corrosion. Such materials could emerge as excellent photocatalysts for the elimination of pollutants from aqueous media using solar energy. In this study, PVP (polyvinyl pyrrolidone)-capped ZnS and CdS nanoparticles, ZnS/CdS and CdS/ZnS core shell nanoparticles were synthesized by microwave irradiation method and characterized using different techniques. The XRD patterns exhibited cubic and hexagonal structures for coated ZnS and CdS nanoparticles, respectively. Morphological evaluation of TEM images showed that the nanoparticles are generally spherical in shape. The UV-visible spectra confirmed a shift in the band gap of coated nanoparticles to longer or shorter wavelengths due to size and potential-well effects. The photocatalytic activity of nanoparticles toward dye degradation under visible light was found to be improved after coating. PVP-capped ZnS and CdS exhibited an enhancement in the initial methylene blue degradation efficiency by a factor of about 1.3. ZnS nanoparticles coated by CdS displayed the initial efficiency 3.2 times higher than bare ZnS. The maximum dye removal was obtained in presence of CdS/ZnS core shells which is 1.4 times more efficient than bare CdS.

Synergetic effect of CuS@ZnS nanostructures on photocatalytic degradation of organic pollutant under visible light irradiation

“…23 Soltani et al synthesized ZnS and CdS nanoparticles which extended the light absorption in the visible region and showed an increased stability against photo-corrosion. 24 Babu et al synthesized Cu/ TiO 2 core-shell nanowires with 3% Cu/TiO 2 and indicated the highest degradation rate of methyl orange. 25 Sunita et al synthesized TiO 2 /CuS core-shell nanostructures.…”

Influence of Co-Dopant on Structural, Optical and Electrochemical Properties of Zinc Sulphide Quantum Dots

“…ZnS is a wide band gap semiconductor material (Eg=3.6 eV). It is commercially used as a phosphor and also as thin-film electroluminescence devices [11,12]. Semiconductor nanocrystals having dimensions smaller than 10 nm are also described as quantum dots [13].…”

“…Efficient photocatalytic processes have been proven to be of a great contribution in treatment of environmental deprivation. Photocatalytic oxidation of organic and biological molecules is one of the most efficient methods for alleviating the negative environmental impact of hazardous wastes and toxic pollutants in aqueous media [6,12]. The superiority of photocatalytic technique in wastewater treatment is due to its advantages over the traditional techniques such as quick oxidation, high efficiency, no formation of polycyclic products and oxidation of pollutants in the low levels [16].…”

Visible light driven photocatalytic hydrogen evolution over CdS incorporated mesoporous silica derived from MCM-48

“…The nano-carbon materials acted as electron collectors and transfer channels because of the well-known delocalized conjugated structure. Semiconductor heterojunctions such as CdS/TiO 2 , CdS/ZnO, CdS/ZnS, and CdS/C 3 N 4 have been widely reported in photocatalysis due to the promoted separation of photo-generated charges at the interface [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. In addition, microporous and mesoporous silica could be used as support for dispersing CdS quantum dots [57][58][59][60][61][62][63][64][65][66][67][68].…”