Oxidation of sulfonamides over LaPtxFe1-xO3±δ perovskites: Elucidation of the degradation mechanism through the study of surface vacancies

Herein we report the oxidative degradation of sulfathiazole (STZ) using hydrogen peroxide (H 2 O 2 ) as an oxidizing agent over a series of LaPt x Fe 1-x O 3±δ (x=0-0.25) perovskites. The study focused on the effect of B-site regulation in multicationic perovskites (AB 1-x B` x O 3±δ ) to investigate the catalytic descriptors responsible for activity in this reaction. The reaction was monitored using UV-Vis spectroscopy and parameters such as catalytic loading, pH, oxidant concentration, and time were studied to find the best reaction conditions. Our results revealed that the structural defects in perovskites materials such as oxygen vacancies (O V ) and relative spin density played a crucial role in activating H 2 O 2 to produce reactive hydroxyl radicals ( ∙ OH), thus facilitating the degradation efficiency. The best catalyst LaPt 0.25 Fe 0.75 O 3±δ with optimum amount of oxygen vacancies achieved up to 99.98% degradation efficiency. The combination of experimental and Density Functional Theory (DFT) calculations served as useful tools to identify catalytic descriptors. Catalytic descriptors such as structural defects, relative spin density, band gaps, adsorption energies, and oxygen vacancies helped determine the catalytic behavior of multicationic perovskites. Overall, a strategic approach for designing high-performance catalysts for degradation reaction has been established. • Modification of the B-site lead to altered surface defects in perovskite systems. • Oxygen vacancies activate hydrogen peroxide, thus enhancing the degradation efficiency. • DFT calculations are central to determination of defects and orientation of antibiotics on catalyst surfaces. • Oxygen vacancies dictate the selectivity of the degradation process.