Bandgap engineering and plasmonically enhanced sun light photocatalyis in Au/Cd1−xZnxS nanocomposites

Pavan P Gotipamul,Shweta Khanna,Maheswaran Rathinam,Siva Chidambaram,Karthik Dilly Rajan

doi:10.1007/s10854-021-06279-6

Abstract

Metal nanoparticles-decorated semiconductor nanomaterials generally hold a series of advantages especially enhanced electron–hole pair lifetime and thus exhibit superior solar energy conversions. In this study, we report a facile solution processing of Au-decorated Cd1−xZnxS, where x = 0, 0.25, 0.5, 0.75, and 1, nanocomposites and their enhanced photocatalytic activity against methylene blue (MB) dye degradations. The Au/CdZnS nanocomposites were investigated for their structural, morphological, optical, and photocatalytic properties. The XRD patterns indicated that the crystalline sizes of CdZnS are found to fall within 1–3 nm. The electron microscopic images publicized that the average particle size of Cd0.25Zn0.75S is 5 nm. The bandgap values of pristine CdS, pristine ZnS, Cd0.75Zn0.25S, Cd0.5Zn0.5S, and Cd0.25Zn0.75S are 2.21 eV, 3.4 eV, 2.29 eV, 2.31 eV, and 2.53 eV, respectively. The optical band gap of the Cd1−xZnxS nanomaterials have got reduced for Au incorporation due to the occurrence of red shift and the enhanced visible region absorption for the incorporation of Au. The visible light photocatalytic effect of the nanocomposites has been evaluated with MB dye degradation reaction under sunlight light exposure. The Au-decorated Cd0.25Zn0.75S nanocompound had exhibited 97% of photocatalytic degradation of MB dye molecules which is 20% higher than the bare Cd0.25Zn0.75S nanocompound.

Highlights

IntroductionThe recombination can be further avoided abruptly via incorporating the plasmonic metal nanoparticles, such as Ag, Au, Pt, and Pd on the surface of the Cd1 − xZnxS nanomaterials [6, 7]
The visible light photocatalytic effect of the nanocomposites have been evaluated with methylene blue (MB) dye degradation reaction under sunlight light exposure
The surface morphology and elemental composition of the photocatalyst were analysed by field- emission scanning electron microscopy (FE-scanning electron micrographs (SEM)) FEI Nova Nano-SEM operating at 15kv, attached with energy dispersive X-ray spectrometer

Summary

Introduction

The recombination can be further avoided abruptly via incorporating the plasmonic metal nanoparticles, such as Ag, Au, Pt, and Pd on the surface of the Cd1 − xZnxS nanomaterials [6, 7]. We have followed co-precipitation methodology for the preparation of Cd1 − xZnxS solid solution followed by the incorporation of Au nanoparticles via ultrasonication assisted SILAR (successive ionic layer adsorption and reaction) technique. The surface morphology and elemental composition of the photocatalyst were analysed by field- emission scanning electron microscopy (FE-SEM) FEI Nova Nano-SEM operating at 15kv, attached with energy dispersive X-ray spectrometer. A typical test was carried out using 50 mg of as prepared photocatalyst nanomaterials and 50 ml of (10mg/L) MB dye solution. At every certain time interval, 3 ml of dye solution was collected after placed under bright sunlight and centrifuged to remove the catalysts.

Result

Findings

Conclusions