Hydrothermally synthesized strontium-modified ZnO hierarchical nanostructured photocatalyst for second-generation fluoroquinolone degradation

The utilization of visible light semiconductor photocatalyst was considered an effective technique to treat hazardous organic pollutants. From the focus of increasing the photocatalytic performance of zinc oxide, different concentrations of (5, 10, and 15%) strontium (Sr2+)-substituted ZnO hierarchical nanostructures were prepared by hydrothermal method. The sample characterizations were investigated by XRD, HR-SEM, photocurrent, EIS, and TOC analysis. The optical property of the samples was investigated by UV–visible diffuse reflectance spectra and photoluminescence (PL). The average crystalline size and strain (tensile strain) were calculated using the Williamson–Hall (W–H) plot. The hierarchical morphology of the sample was observed through SEM, and EDS confirms about the substitution of Sr. Occurrence of a peak at 142.7 eV in the XPS survey spectrum confirms the presence of Sr2+. Degradation of pollutant by 10% Sr–ZnO increases degradation efficiency from 44 to 97% with a time delay. The significant contribution of superoxide anions (•O2−) in degradation was obtained through scavenger analysis. TOC test confirms the decrement of organic carbon content. Reduction in electron–hole recombination was sufficiently attained because of the Sr atom, which functions as an electron transmitter. After degradation, the unchanged crystallinity nature of 10% Sr–ZnO reveals excellent stability and makes it a good candidate in environmental remediations.