Efficient Sunlight-Driven Photocatalytic Degradation of Metronidazole in Wastewater Using Polyhedral Silver-Doped SrTiO3 Nanostructures

In this study, we examine the effect of silver (Ag) doping on the structural, optical, morphological, photocatalytic, and degradation properties of SrTiO₃ (STO) for the degradation of the pollutant metronidazole. XRD analysis confirmed the formation of pure SrTiO₃ with a cubic structure, and the incorporation of Ag was evidenced by additional characteristic diffraction peaks. Lattice parameters for both STO and Ag-STO were determined using Rietveld refinement. FTIR analysis identified characteristic vibration bands of STO. SEM micrographs revealed polyhedral-shaped particles for both STO and Ag-STO, with the latter exhibiting smaller grain size. UV–Vis measurements indicated a direct band gap transition for both STO and Ag-STO, with no change in the band gap upon doping. PL analysis showed a broad emission band centered at 455 nm for STO and additional emission peaks for Ag-STO. These PL results helped establish an energy diagram outlining possible transition mechanisms within the materials. The degradation capabilities of STO for metronidazole, and the critical role of Ag doping in enhancing these capabilities, were clearly demonstrated.