Comparative Study of TiO₂/CuS Core/Shell and Composite Nanostructures for Efficient Visible Light Photocatalysis

Abstract

An enduring impediment in the photocatalysis domain is the rapid recombination of photoinduced charge carriers. One viable strategy to realize efficient separation of photoinduced charge carriers is to design core/shell nanostructures. In this context, our work explains the substantial separation of photocarriers and enhanced light harvesting in TiO 2 nanostructures following the realization of core/shell geometry with CuS. We demonstrate the design of the TiO 2 /CuS core/shell nanostructures, utilizing a surface-functionalizing agent, 3-mercaptopropionic acid, and offering commendable visible light driven photocatalytic performance for degradation of virulent organic pollutants of dye wastewater, like methylene blue (MB). To validate the merits of the TiO 2 /CuS core/shell nanostructures, we have also designed TiO 2 /CuS composite nanostructures under similar conditions (without utilizing the surface-functionalizing agent, 3-mercaptopropionic acid). Successful realization of TiO 2 /CuS nanostructures (core/shell and composite) was concluded from the PXRD, FESEM, TEM, HRTEM, EDS elemental mapping, and DRS studies. The resulting core/shell nanostructures have propitious photocatalytic performance (∼90%) over composite nanostructures (∼58%), which could be scrutinized in terms of core/shell geometry, maximizing the interfacial contact between TiO 2 and CuS and enabling retardation in the recombination rate of the photoinduced charge carriers by confining electrons mainly in one component (core) and holes in the other component (shell).To have the best photocatalytic performance from the TiO 2 /CuS core/shell nanostructures, we also determined the optimum amount of photocatalyst (0.3 g/L) and organic pollutant dye concentration (0.003 g/L) required for visible light driven degradation of MB. A credible mechanism of the charge transfer process and mechanism of photocatalysis supported from trapping experiments in the TiO 2 /CuS nanostructures for the degradation of an aqueous solution of MB is also explicated. Degradation intermediates analysis performed using mass spectroscopy (MS) studies showed that MB dye degradation is initiated by a demethylation pathway. Our work also highlights the stability and recyclability of a core/shell nanostructures photocatalyst and supports its potential for environmental applications. We thus anticipate that our results bear broad potential in the photocatalysis domain for the design of a visible light functional and reusable core/shell nanostructures photocatalyst.

A Facile Platform for Photocatalytic Reduction of Methylene Blue Dye By CdSe-TiO2 Nanoparticles

“…CdS and CdSe nanoparticle deposited on ordered TiO 2 nanotubes [20] were found to efficiently degrade methylene orange dye (up to 95%) within 120 min of visible light irradiation. Ninety percent MB dye degradation was achieved in the presence of visible light by TiO 2 /CuS composite nanostructure, synthesized via surface functionalization route [21]. In all the above-mentioned reports, there was a requirement of integrating TiO 2 with semiconductors into a single nanoscale heterostructure, which in itself requires extensive synthesis.…”

Titanium dioxide‐coated biochar composites as adsorptive and photocatalytic degradation materials for the removal of aqueous organic pollutants

“…Photocatalysis based on TiO 2 is particularly attractive because of its wide availability, low cost, and non‐toxicity . Recently, TiO 2 and its composites have been extensively utilised as photocatalysts for the removal of dyes from wastewater .…”

“…1,2 Photocatalysis based on TiO 2 is particularly attractive because of its wide availability, low cost, and non-toxicity. [18][19][20][21] Recently, TiO 2 and its composites have been extensively utilised as photocatalysts for the removal of dyes from wastewater. 22 For example, Zhang et al demonstrated a UV-visible light photocatalysis process for the degradation of azo dyes using TiO 2 .…”

Highly efficient and visible light driven Ni0.5Zn0.5Fe2O4@PANI modified BiOCl heterocomposite catalyst for water remediation

“…For BiOCl, almost negligible peaks were detected whereas a gradual increase in peak intensity was observed for NPB20 composite as the visible light irradiation time increases from 0 to 60 min ( Figure 14). This indicates that the fluorescence is caused by chemical reactions of terephthalic acid with ȮH formed on the NPB20/water interface via photocatalytic reactions [65]. [60,66].…”