Preparation, parameter optimization of anodized ZnO films and their photocatalytic performance in organic dye degradation in wastewater

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2022-08, Vol.128 (8), Article 697
• Main Authors: Zhu, Enlong, Li, Fei, Zhao, Qian, Hu, Te, Guan, Sujun, Lu, Yun, Hao, Liang
• Format: Article
• Language: English
• Subjects: Annealing; Anodizing; Applied physics; Catalytic activity; Characterization and Evaluation of Materials; Condensed Matter Physics; Crystal defects; Crystal structure; Crystallinity; Current carriers; Defect annealing; Electrolytes; Machines; Manufacturing; Materials science; Metal foils; Nanorods; Nanotechnology; Nanowires; Optical and Electronic Materials; Optimization; Photocatalysis; Photodegradation; Physics; Physics and Astronomy; Process parameters; Processes; Raman spectra; Resultants; Surfaces and Interfaces; Thin Films; Wastewater; Zinc oxide
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-022-05856-8

Photocatalytic ZnO films were prepared by facile anodization followed by annealing. The influence of some processing parameters, including applied potential, anodization time, electrolyte concentration, and annealing temperature, on the resultants’ composition and photocatalytic activity of the prepared films, was investigated. The XRD, Raman spectra, and SEM analysis show that the nano-sized grass-like microstructure was formed with nanowires or nanorods. The films were composed of ZnO and Zn 5 (CO 3 ) 2 (OH) 6 . Higher applied potential, longer anodization time, and higher electrolyte concentration made for the formation of ZnO, leading to higher photocatalytic activity. Higher annealing temperature decreased the defects and thereby increased the crystallinity of ZnO. Higher crystallinity restrained the recombination of photogenerated charge carriers; thereby, enhancing the photocatalytic activity. However, a high annealing temperature, even at 523 K, led to the adhesion decrease of the prepared films on Zn foils and thereby the films’ exfoliation. That decreased the photocatalytic performance of the as-annealed films. Therefore, the annealing temperature has a moderate value to achieve the optimal photocatalytic performance. The present systematic study on the preparation and processing parameters of ZnO by anodization followed by annealing has helpful guiding significance for the fabrication of photocatalyst films with high photocatalytic performance.