Tungsten-doped SrTiO₃ for Boosting Photocatalytic Removal of Cr(VI) and Antibiotic Tetracycline: Charge Redistribution and Band Engineering

Abstract

The simultaneous photocatalytic removal of hexavalent chromium [Cr(VI)] and tetracycline (TC) presents a critical challenge in wastewater remediation due to their synergistic environmental persistence and toxicity. This study demonstrates tungsten-doped SrTiO₃ (W-SrTiO₃) as an efficient dual-functional photocatalyst through strategic electronic structure engineering. By substituting B sites (Ti sites) of SrTiO₃ (perovskite-structured, ABO₃-type) with high-valence W⁶⁺ ions, controlled doping induces localized charge redistribution within the SrTiO₃ lattice, creating electron-trapping sites at dopant positions to prolong carrier lifetimes. Concurrently, oxygen vacancy engineering suppresses mid-gap recombination centers, synergistically enhancing charge separation efficiency. Band structure modulation widens the bandgap (3.31→3.36 eV) through coordinated upward valence band (+1.79→+1.82 V vs. NHE) and downward conduction band (-1.52→-1.54 V) shifts, thereby extending the thermodynamic driving force for redox reactions. The elevated conduction band strengthens electron reduction capacity for Cr(VI), while the upshifted valence band retains sufficient oxidative potential for TC mineralization. This dual-functional capability enables effective treatment of mixed pollutant system, exhibiting pseudo-first-order rate constants of 0.12001 min^-1 for Cr(VI) and 0.17280 min^-1 for TC, representing 9.2-fold and 11.3-fold enhancements over pristine SrTiO₃, respectively. This work establishes a dual-engineering strategy integrating dopant-induced charge redistribution with oxygen vacancy optimization for advanced photocatalytic water purification.

Keywords

Tungsten-doped SrTiO₃ / Charge redistribution / Band structure tuning / Chromium / Tetracycline

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RIGHTS & PERMISSIONS

Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH