Defect engineering for enhanced optical and photocatalytic properties of ZnS nanoparticles synthesized by hydrothermal method

Abstract

Defect engineering is a promising method for improving light harvesting in photocatalytic materials like Zinc sulphide (ZnS). By altering the S/Zn molar ratio during hydrothermal processes, Zn and S defects are successfully introduced into the ZnS crystal. The band structures can be modified by adding defects to the crystal structure of ZnS samples. During the treatment process, defects are formed on the surface. XRD and Raman studies are used for the confirmation of the crystallinity and phase formation of the samples. Using an X-ray peak pattern assessment based on the Debye Scherer model, the Williamson-Hall model, and the size strain plot, it was possible to study the influence of crystal defect on the structural characteristics of ZnS nanoparticles. The band gap (Eg) values were estimated using UV–Vis diffuse spectroscopy (UV–Vis DRS) and found that the Eg is reduced from 3.28 to 3.49 eV by altering the S/Zn molar ratio. Photoluminescence study (PL) shows these ZnS nanoparticles emit violet and blue radiations. In keeping with the results of XRD, TEM demonstrated the nanoscale of the prepared samples and exhibited a small agglomeration of homogenous nanoparticles. Scanning electron microscopy (SEM) was used to examine the surface morphology of the ZnS particles. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS) were used to evaluate and validate the elemental composition. XPS results indicate the presence of defects on the prepared ZnS nanoparticles. For the investigation of vacancy-dependent catalytic activity under exposure to visible light, defective ZnS with different quantities of Zn and S voids are used as catalysts. The lowest S/Zn sample, ZnS0.67 and the highest S/Zn sample, ZnS3, show superior photocatalytic activity.

Optimization of Electrochemical Sensitivity in Anticancer Drug Quantification through ZnS@CNS Nanosheets: Synthesis via Accelerated Sonochemical Methodology

“…2 A-D. Based on the XPS analysis of Fig. 2 , confirm the elements and oxidation state of the elements such as Zn 2p (Zn 2+ ), S 2p (2 - ), C 1 s (4 + ) and N 1 s (3 - ) [ 27 ]. The peak separation of the peaks at 1022.5 eV and 1045.9 eV in Zn 2p spectrum ( Fig.…”

“…The peak separation of the peaks at 1022.5 eV and 1045.9 eV in Zn 2p spectrum ( Fig. 2 A) and which was originated from the Zn 2p 3/2 and Zn 2p 1/2 of ZnS [ [27] , [28] ]. In other hand, the S 2p could be deconvoluted into the peaks at 162.5 eV and 163.2 eV, assigned to S 2p 3/2 and S 2p 1/2 of ZnS ( Fig.…”

“…In other hand, the S 2p could be deconvoluted into the peaks at 162.5 eV and 163.2 eV, assigned to S 2p 3/2 and S 2p 1/2 of ZnS ( Fig. 2 B) [ [27] , [29] ].

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Luminescence and photocatalytic degradation of indigo carmine in the presence of Sm3+doped ZnS nanoparticles

“…It has been demonstrated that when the energy of the radiation exceeds the band gap width of ZnS, matched holes (h + ) grow in the valence band (VB), creating a “electron hole” pair. In contrast, excited electrons in the valence band (VB) can jump into the conduction band (CB) 44 . According to Eqs.…”

“…The abovementioned processes demonstrate that photocatalytic degradation is possible when soluble oxygen and H 2 O are present. There have been other reports of similar methods for the photocatalytic destruction of dyes 44 . As a result, ZnS nanoparticles have the potential to purify them, which causes photocatalysis to destroy indigo carmine dye.…”