Dual role of Au-NPs for Schottky effect and SPR electron injection over CdS surfaces for photocatalytic applications

Abstract

In this work, CdS and Au-loaded CdS photocatalysts were successfully synthesized by the hydrothermal method. The gold nanoparticles were in-situ developed over the surfaces of CdS support via chemical reduction method. To find the surface morphology and optical properties, the as-synthesized photocatalysts were characterized using XRD analysis, Raman spectroscopy, UV–Vis-DRS, PL, AFM, SEM and EDX techniques. To evaluate the charge separation efficiency of materials photochemical experiment (i.e. Photocurrent response and EIS) were conducted. The surface area and oxidation state were studies via XPS, BET techniques. UV–Vis spectrophotometer was used to examine the photocatalytic degradation activities. Results of this work depict that existence of Au nanoparticles over the surface of CdS boosts the photocatalytic performance. The higher activities were accredited due to hot electron injection of Au-NPs (SPR effect) to the conduction band. Higher charge separation is inevitable due to intimate effect of Schottky junctions and new Fermi levels generation during the photoreactions. It has been found that radical like •O2− and h+ are the main active species for the degradation reactions. To evaluate the ideal conditions, various factors have been investigated for the methyl orange (MO) degradation. On the basis of encouraging results, we can recommend this work for other potential applications.