Promote reactants activation and key intermediates formation for facilitated toluene photodecomposition via Ba active sites construction

The establishment of active sites can obviously promote photocatalytic efficiency, but its role in activation mechanism and generation of key reaction intermediates during toluene mineralization remains unsolved. We reveal that the benzene ring opening is the rate-limiting step of mineralization reaction, and the inert CC bond in the ring is the crucial reason for the shortage mineralization of previous catalysts. In this work, the Sr1-xBaxTiO3 solid solution was prepared as a model photocatalysts to reveal the mechanism of photocatalytic toluene degradation. The electronic local center was constructed at the substituted Ba sites, which intensified the charge transfer between catalyst surface and adsorbed molecules. The strong oxidative species generated by enhanced activation further facilitated the conversion of toluene to generate benzoic acid as the key reaction intermediate before ring-opening. Through the combined theoretical calculation and in situ characterization methods, it was revealed that efficient degradation and stable mineralization of toluene in photocatalysis can be achieved by activating toluene and promoting the formation of key reaction intermediates. This study could advance a new viewpoint for safe and efficient photocatalytic air purification.