Preparation of Pt(II/IV)Clx/BiOHC2O4/Bi2O2CO3 composite microrods with enhanced photocatalytic performance for levofloxacin degradation in water

Abstract

BiOHC2O4 microrods were initially prepared via a straightforward microwave hydrothermal method. These microrods then served as templates for the growth of BiOHC2O4/Bi2O2CO3 composites via anion exchange. Pt loading onto the composite microrods was achieved through photodeposition and chemical reduction methods. The obtained samples were analyzed by XRD, SEM, TEM, XPS, FT-FIR, UV–Vis DRS, PL, N2 physical adsorption, photocurrent and Nyquist impedance measurements. The photocatalytic performance of the fabricated materials for levofloxacin degradation was evaluated under both UV–visible and visible light irradiation. The results showed the formation of Pt(II/IV)Clx species on hierarchical BiOHC2O4/Bi2O2CO3 structure following photodeposition, while metallic Pt was produced via NaBH4 reduction. Pt(II/IV)Clx/BiOHC2O4/Bi2O2CO3 composites displayed superior photocatalytic performance under both light conditions. This enhanced performance can be linked to the presence of Pt(II/IV)Clx, which significantly improves light absorption and facilitates the transfer of photoelectrons and holes (e− and h+). Pt(II/IV)Clx served as a dual-functioning agent, acting as both a photosensitizer to enable visible light activity and as an inhibitor suppressing the recombination of photogenerated carriers. Loading around 4%Pt(wt%), BiOHC/BiOC demonstrated the highest rates of TOC removal, under full light spectrum irradiation for 75 min and visible light irradiation for 300 min, respectively.