Enhanced piezo-photocatalysis in Bi_0.5Na_0.5TiO₃@Ag composite to efficiently degrade multiple organic pollutants

The synergistic piezo-photocatalysis with enhanced efficiency for degrading obstinate pollutants in wastewater is considered as an advanced way to ameliorate the global water contamination. In this work, we report a facile route to construct the Bi_0.5Na_0.5TiO₃@Ag composite by photoreduction of AgNO₃ to obtain Ag on Bi_0.5Na_0.5TiO₃ nanoparticles. And the composite was used to degrade three representative pollutants, i.e. ciprofloxacin, methyl orange and mitoxantrone hydrochloride. Remarkably, for methyl orange solution with the initial concentration of 10 mg/L, the degradation rate constant of the composite reached 0.051 min^-1. H⁺ and •O₂^- play a major role in this degradation process, verified by the radical quenching experiments. The absorption platform of Bi_0.5Na_0.5TiO₃ was located in the UV region, after introducing Ag in the composite, the absorption region broadened to both UV and visible light, greatly promoting the response to light. Simultaneously, the induced piezo-potential by mechanical energy in Bi_0.5Na_0.5TiO₃ hindered the carrier recombination, resulting in high-efficiency synergistic piezo-photocatalytic process. This work provides a paradigm to innovate both material and catalytic way for degrading multiple organic pollutants.