Effects of doping zinc oxide nanoparticles with transition metals (Ag, Cu, Mn) on photocatalytic degradation of Direct Blue 15 dye under UV and visible light irradiation

Abstract

Background Azo dyes represent the most commonly used group of dyes in the textile industry. These organic dyes are mainly resistant to biodegradation and may exhibit toxic and carcinogenic properties. The purpose of this study was to investigate the effects of doping zinc oxide (ZnO) nanoparticles (NPs) with transition metals (silver, manganese, and copper) on the photocatalytic efficiency of ZnO NPs in the removal of Direct Blue 15 dye from aqueous environments under ultraviolet (UV) radiation and visible light irradiation. Methods One or two metals were used for doping the NPs. In total, seven types of undoped and transition metal-doped NPs were synthesized using the thermal solvent method with ZnO precursors and transition metal salts. The characteristics of the synthesized NPs were determined based on the scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Xray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), atomic force microscopy (AFM), and zeta potential measurements. Results The produced ZnO NPs did not exhibit any particular photocatalytic activities under UV radiation and visible light irradiation. The highest removal efficiency under UV radiation was about 74% in the presence of silver-doped ZnO NPs, while the maximum efficiency under visible light was 70% in the presence of copper-doped ZnO NPs. The lowest removal efficiency Highlights • Transition metal-doped ZnO NPs was used for photocatalytic removal of Direct Blue 15 dye. • Photocatalytic activity of ZnO NPs was improved after doping with Ag, Mn, and Cu. • SEM, XRD, FTIR, and AFM corroborated the synthesis of transition metal-doped NPs. • Photocatalysis using Ag-doped ZnO NPs could degrade 74% of dye under UV radiation. • About 70% of dye could be removed using Cu-doped ZnO NPs under visible light.

Highly Efficient Visible Light Active Doped ZnO Photocatalysts for the Treatment of Wastewater Contaminated with Dyes and Pathogens of Emerging Concern

“…A 1.5% Nd-Gd codoped ZnO resulted in 93% photocatalytic breakdown of MB in 180 min [67]. The photocatalytic efficiency of other doped zinc oxides for the degradation of various dyes can be seen in Table 1 [68][69][70][71][72][73][74][75][76][77]. Thus, it can be concluded that doping increases the photocatalytic characteristics of ZnO nanostructures.…”

Significantly enhancement of sunlight photocatalytic performance of ZnO by doping with transition metal oxides

“…It is well known the use of semiconductors like TiO 2 3 and ZnO for this purpose 4 . Likewise, it is known that the wide band gap of these metal oxides limits their use in the visible range 5 . Additionally, rapid recombination of hole-electrons pairs is another limitation of ZnO 6 .…”

Efficient and Rapid Photocatalytic Degradation of Methyl Orange Dye Using Al/ZnO Nanoparticles

“…Therefore, it has become an important issue to extend the optical absorption of ZnO from the UV region to visible region for photocatalytic applications. Several methods have been proposed to improve properties of ZnO by controlling the size and morphology of particles [ 38 , 39 ], doping with metals and nonmetals [ 40 , 41 , 42 , 43 ] and coupling with other semiconductor catalysts [ 44 , 45 , 46 ]. The surface defects by introducing metal elements have been reported to play an important role in improving photocatalytic activities over a wide range of wavelengths by reducing the bandgap energy.…”