Piezo-enhanced charge carrier separation over plasmonic Au-BiOBr for piezo-photocatalytic carbamazepine removal

The piezo-photocatalytic effect of Au decorated bismuth oxybromide (BiOBr) was investigated to elucidate the regulation of built-in electric field on charge carrier dynamics and exploit the potential of multi-field coupled environmental purification. Physicochemical properties of Au-BiOBr such as the piezoelectricity, photoresponse characteristics, and charge separation efficiencies were thoroughly analyzed, meanwhile the degradation of carbamazepine (CBZ) was chosen to evaluate the catalytic performance of this system. The piezo-photocatalytic removal of CBZ reached 95.8% within 30 min, and the rate constant is 1.73 times higher than the sum of individual piezo- and photocatalytic ones. The results attribute to not only the modification of Au nanoparticles that accelerates charge transfer and improves light absorption, but also, more importantly, the piezoelectric effect of BiOBr that amplifies the built-in electric field and modulates the band structure alignment. This work demonstrates a promising environmental remediation strategy via the co-utilization of solar and mechanical energy in nature.