Bravecount's MWCNTs Used in Electrochemical Science Research

Origin: International Journal of Electrochemical Science

Int. J. Electrochem. Sci., 16 (2021) Article ID: 210733, doi: 10.20964/2021.07.63

Robust Visible-Light Photocatalytic Norfloxacin Degradation from Aqueous Solution Using Ni-doped ZnO/ MWCNTs Nanocomposite

By Shiwei Wen, Mi Chen and Hui Cao

This study revealed the preparation of Ni-doped ZnO/ MWCNTs nanocomposite as a photocatalyst for degradation of norfloxacin as quinolone under UV and visible light irradiations. The chemical synthesis method was used for functionalization of MWCNTs to prepare Ni-doped ZnO/MWCNTs nanocomposite. SEM and XRD analyses of the nanocomposite revealed that it was composed of Nidoped ZnO spherical nanoparticles attached to a tangled network of MWCNTs. EIS and CV studies revealed that Ni-doped ZnO/MWCNTs composites had improved interfacial charge transfer efficiency. Optical studies revealed that the band gap energy for Ni-doped ZnO/MWCNTs nanocomposites was 2.90 eV, and anchoring Ni into the MWCNTs and ZnO lattices resulted in a narrowing of the nanocomposite band gap. The photocatalytic studies revealed that after 30, 60, 120, and 160 minutes of visible irradiation, respectively, and 40, 70, 150, and 200 minutes of UV irradiation, respectively, complete degradation of 10, 20, 50, and 100 mg/l of norfloxacin was obtained. Results indicated that the synergetic effect of functionalized MWCNTs and Ni NPs in anocomposite caused the band gap to narrow and could provide higher redox abilities under visible light irradiation and enhance the range of a sensitization process due to form facile electron transfer and the heterojunction formation.

Keywords: Photocatalyst; Quinolones; Norfloxacin; MWCNT; ZnO; Nanocomposite; Electrochemical impedance spectroscopy

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2. MATERIALS and METHOD

MWCNTs, ZnO NPs, Ni-doped ZnO NPs, ZnO/ MWCNTs and Ni-doped ZnO/MWCNTs nanocomposites were synthesized on Si and glassy carbon electrode as substrates. In order to preparation of ZnO/MWCNTs and Ni-doped ZnO/MWCNTs nanocomposites, 5g MWCNTs (97.5%, Chengdu Bravecount Trading Co., Ltd., China) was ultrasonically functionalized in concentrated H2SO4 (98%, Sigma-Aldrich) and HNO3 (70%, Sigma-Aldrich) with a volume ratio of 3:1 at 50°C for 6 hours. The functionalized MWCNTs were filtered and washed several times with deionized water and acetone, respectively. The suspension was then dried in a vacuum oven at 75°C for 12 hours. At 70 °C for 12 hours, 2 g of the final product was ultrasonically distributed in 20 ml dimethyl formamide (DMF, 99.8%, Sigma-Aldrich). The dispersed MWCNTs were then treated with 6 ml of 0.1 M zinc acetate solution (99%, Haihang Industry Co., Ltd., China) and 1 ml of 1 mM nickel nitrate hexahydrate (99%, W&Q Metal Products Co., Limited, China). After 30 minutes of magnetic stirring at 35°C, the sample was centrifuged at 1000 rpm for 5 minutes, washed with deionized water several times, and then dried in an oven at 80°C for 5 hours. The substance was calcined in vacuum for 10 hours at 280°C.

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Origin: Robust Visible-Light Photocatalytic Norfloxacin Degradation from Aqueous Solution Using Ni-doped ZnO/ MWCNTs Nanocomposite