Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

Abstract

Photocatalytic activity of semiconductor nanostructures is gaining much importance in recent years in both energy and environmental applications. However, several parameters play a crucial role in enhancing or suppressing the photocatalytic activity through, for example, modifying the band gap energy positions, influencing the generation and transport of charge carriers and altering the recombination rate. In this regard, physical parameters such as the support material and the irradiation source can also have significant effect on the activity of the photocatalysts. In this work, we have investigated the role of reduced graphene oxide (RGO) support and the irradiation source on mixed metal chalcogenide semiconductor (CdS–ZnO) nanostructures. The photocatalyst material was synthesized using a facile hydrothermal method and thoroughly characterized using different spectroscopic and microscopic techniques. The photocatalytic activity was evaluated by studying the degradation of a model dye (methyl orange, MO) under visible light (only) irradiation and under natural sunlight. The results reveal that the RGO-supported CdS–ZnO photocatalyst performs considerably better than the unsupported CdS–ZnO nanostructures. In addition, both the catalysts perform significantly better under natural sunlight than under visible light (only) irradiation. In essence, this work paves way for tailoring the photocatalytic activity of semiconductor nanostructures.

Preparation Of ZnO/Co3O4 Hollow Microsphere By Pollen‐biological Template And Its Application In Photocatalytic Degradation

“…In addition, carriers can be generated in the two semiconductors. Considering the more cathode VB of Co 3 O 4 , the transfer of electrons from the CB of Co 3 O 4 to the CB of ZnO and the transfer of hole from the VB of ZnO to the VB of Co 3 O 4 can occur simultaneously . Therefore, the recombination of photogenerated charges can be suppressed under the irradiation of visible light.…”

N-doped ZnO–MoS2 binary heterojunctions: the dual role of 2D MoS2 in the enhancement of photostability and photocatalytic activity under visible light irradiation for tetracycline degradation

“…16 Over the past few years, unremitting efforts have been made to improve the photocatalytic efficiency of ZnO based semiconductor materials and to enhance the absorption range towards visible region by adopting various strategies, such as doping with noble metals to form ZnO-Au, 17 ZnO-Ag, 18 and ZnO-Pt 19 nanocomposites, coupling with other semiconductor materials, composite formation with carbon based materials, such as graphene, etc. [20][21][22][23] Hence, it is always desirable to develop a photocatalyst with enhanced response from UV to visible spectral range, which constitutes about 43% of solar spectrum.…”

ZnO-graphene quantum dots heterojunctions for natural sunlight-driven photocatalytic environmental remediation

“…Graphene has attracted great attention since its discovery in 2004 because of its fascinating physical properties and has been explored intensively for photocatalysis [32,33].…”

“…Some previous reports from our group have focused on nanocomposites of ZnO with narrow band gap materials (MoS 2 , CdS) and two dimensional (2D) carbonaceous material (reduced graphene oxide) for the removal of organic pollutants from water [22,26,32]. In this work, we focus on heterojunction formation using ZnO and GQD, which can be robust and promising catalyst compare to their individual components.…”