pH-Dependent Visible Light Photocatalytic Efficiency of Aminophenol-Functionalized ZnO for Brilliant Blue G Degradation

Zinc oxide (ZnO) is a common photocatalyst for dye degradation, but its efficiency is limited by surface properties, photocorrosion, and pH sensitivity. This study functionalized ZnO with 2-aminophenol (ZnO-AP) to enhance dye adsorption and stability under varying pH. FTIR, XRD, and UV-Vis confirmed successful synthesis, with ZnO-AP showing a reduced band gap for improved visible light absorption. Photodegradation tests using Brilliant Blue G (BBG) revealed that ZnO-AP has the highest efficiency (36.17%) at pH 4, driven by strong electrostatic interactions. Performance decreased at pH 7 and 11 due to reduced dye adsorption, especially at basic pH with electrostatic repulsion. Functionalization also protected ZnO against photocorrosion, improving stability in acidic conditions. These results highlight 2-AP functionalization as a promising strategy to enhance the photocatalytic performance of ZnO across pH ranges.