Precursor impurity-mediated effect in the photocatalytic activity of precipitated zinc oxide

Abstract

Photocatalytic degradation of pollutants using nanoparticles presents a promising method globally. However, effectively harnessing light absorption while mitigating recombination and nanoparticle agglomeration remains challenging. Here, we explore the synthesis and characterization of zinc oxide nanoparticles for photocatalytic dye removal in water. The ZnO catalyst, controlled by impurity amount, is developed, demonstrating a notable impact on photolytic performance. Various zinc precursors, namely, zinc acetate, zinc sulfate, zinc nitrate, and zinc chloride, were used in the precipitation technique. Optical characterization showed distinct band transitions and UV-dominant absorption peaks, indicating the presence of different impurities in each precursor. Photocatalytic performance is assessed using Rhodamine B decomposition with the sample prepared from zinc acetate, demonstrating enhanced photocatalytic activity attributed to its larger surface area, surface defects, and superior morphology, enabling efficient organic pollutant degradation. Oxygen vacancies aid in charge carrier separation, crucial for effective photocatalysis. The material's intense interaction with pollutants and a high photocurrent density of 5.18 µAcm−2 highlight superior electron–hole pair separation capabilities influenced by morphology and impurity-generated defects, significantly boosting its overall photocatalytic reaction. These findings emphasize the critical role of precursor selection in designing effective ZnO-based photocatalysts, water treatment, and environmental remediation applications.