Optimizing the structural and photocatalytic performance of Ag‐decorated ZnO/Zn(OH)₂ nanoparticles for RhB degradation

Abstract

In this study, as‐prepared and Ag‐decorated ZnO/Zn(OH)2 composite nanoparticles (NPs) were obtained using the sol–gel technique. First, the effect of aging on the structural, optical, and morphological features was examined. Ag NPs can interact with the electronic structure of ZnO/Zn(OH)2 NPs, resulting in changes in their energy levels. It was found that the composite NPs obtained after 6 h solution aging increased in full width at half maximum and good crystallinity of the structures from the X‐ray diffraction (XRD) measurements. The Raman spectrum supports the experimental data obtained from XRD and Fourier transform infrared, a material containing a mixture of ZnO and Zn(OH)2. From the morphological study, Ag NPs were successfully decorated on the ZnO/Zn(OH)2 surface, and composite NPs did not change the morphological appearance of the structure. Second, the photocatalytic performance of the samples was investigated. In the experimental setting, ultra‐violet A light was employed as the irradiation source, whereas rhodamine B (RhB) was used as the dyestuff. The photo‐degradation of the RhB dyestuff on composite NPs was observed to be 98.5% and 92.5% for 6 and 2 h aged samples, respectively. On Ag NPs, the catalytic performance of the sample was increased up to 95% after 180 min.

Facile Preparation of Magnetically Separable Fe3O4/ZnO Nanocomposite with Enhanced Photocatalytic Activity for Degradation of Rhodamine B

“…As shown in Figure 3 b, Fe 3 O 4 /ZnO displays three apparent peaks. The broad absorption band in the range of 3000~3500 cm −1 corresponds to the O-H stretching vibrations of adsorbed water and hydroxyl groups in the samples [ 22 , 25 , 27 ]. In the 1000 to 1600 cm −1 region, the absorption band at ~1633 cm −1 is attributed to the C=O stretching vibration of carboxylic organic acids or the bending vibration of O-H bonds from H 2 O molecules [ 25 , 27 , 29 ], due to the use of zinc acetate, sodium citrate, and sodium hydroxide.…”

“…The broad absorption band in the range of 3000~3500 cm −1 corresponds to the O-H stretching vibrations of adsorbed water and hydroxyl groups in the samples [ 22 , 25 , 27 ]. In the 1000 to 1600 cm −1 region, the absorption band at ~1633 cm −1 is attributed to the C=O stretching vibration of carboxylic organic acids or the bending vibration of O-H bonds from H 2 O molecules [ 25 , 27 , 29 ], due to the use of zinc acetate, sodium citrate, and sodium hydroxide. It also revealed that a few hydroxide radicals were adsorbed on the surface of the composite material, which would make a contribution to high photocatalytic performance for RhB degradation by facilitating the generation of active ·OH radicals.…”

“…As an efficient photocatalyst, ZnO has also demonstrated many intriguing qualities, including chemical and physical stability, strong oxidation strength, environmental friendliness, and low price [ 21 , 22 , 23 ]. However, the utilization of ZnO was not fulfilled due to its higher bandgap of ~3.3 eV [ 24 , 25 ], resulting in ZnO only absorbing 5% of the solar energy in UV light and exhibiting low degradation activity for organic pollutants [ 1 ], which limited its practical applications [ 26 , 27 ]. To overcome this drawback and improve the catalytic efficiency, an effective strategy is to utilize metal oxide particles including metal doping, constructing heterojunctions, or nanocomposites to tune the electronic structure of the host, thereby reducing the band gap [ 8 , 10 , 11 , 28 , 29 ].…”