Aliovalent Doping of SrTiO3 for Photocatalytic Pollutant Remediation

Chemical pollution has a significant impact on the environment and human health, requiring immediate remediation. Photocatalysis has been used for various pollutant remediation strategies but is limited by efficiency. Aliovalent doping SrTiO3 with Al has demonstrated significant improvements in photocatalytic water splitting. In this study, we explore the effect of Al-doping SrTiO3 for the degradation of organic molecules, anionic dye-methyl orange and alkyl halide pesticide- 2,4-dichlorophenoxyacetic acid. SrTiO3 nanoparticles were synthesised via a solid state, high temperature synthesis, followed by flux-mediated doping of Al in various mol % (0-20%). High resolution electron microscopy was used to identify a before unseen layer of enriched Al at the particle surface with high (>5mol%) doping. This surface effect potentially explains previous findings of diminishing activity with higher Al-doping. Aliovalent doping of SrTiO3 in photocatalytic pollutant degradation reactions showed a significant improvement in activity, with 0 mol% (Al from crucible) showing highest degradation rate. Radical intermediate scavenger experiments revealed that superoxide anions were a key species in the photocatalytic degradation. A chlorinated pesticide was successfully degraded, showing C-Cl bond cleavage indicating this material could be used for the remediation of textile and persistent organic pollutants.