Enhanced photocatalytic efficiency of SrTiO3 through La-Nb dual doping via a novel microwave-assisted sol-gel auto-combustion technique

Strontium titanate (SrTiO 3 ) is a well-known photocatalyst; however, its performance is limited by rapid electron-hole recombination. In this study, La–Nb co-doped SrTiO 3 (Sr 1- x La x Ti 0.9 Nb 0.1 O 3 , SLTNO) photocatalysts with varying La content ( x = 0.03–0.10) were successfully synthesized using a microwave-assisted sol-gel auto-combustion method. XRD and Rietveld refinement analysis confirmed a phase-pure cubic perovskite structure, while FESEM observations revealed a morphological evolution from irregular grains to more faceted nanocube-like particles with increasing La content. Optical and electrochemical characterization, including UV–vis spectroscopy, photoluminescence (PL) excited at 327 nm, and Nyquist impedance analysis, suggested a lower electron-hole recombination tendency and improved interfacial charge-transfer behavior upon co-doping. The photocatalytic decolorization efficiency (% DE ) of methylene blue (MB) and tetracycline (TC) under UV irradiation was significantly improved by La–Nb co-doping. Radical scavenger tests identified superoxide radicals (O 2 • ⁻) and holes (h⁺) as key active species. These findings demonstrate the potential of SLTNO as a promising photocatalyst and indicate that the adopted synthesis method is effective for tuning the structural and interfacial properties relevant to photocatalytic performance. • First successful synthesis of La-Nb co-doped SrTiO 3 via a novel microwave-assisted sol-gel auto-combustion method. • Higher La content exhibited improved methylene blue (MB) and tetracycline (TC) decolorization under UV irradiation. • Enhanced photocatalytic activity is mainly associated with improved charge-transfer efficiency. • OH • , h + , and O 2 • ⁻ dominate MB degradation, while O 2 • ⁻ and h + dominate TC degradation.