Polarization field engineering of piezoelectric materials is considered as an advisable strategy in fine-tuning photocatalytic performance which has drawn much attention recently. However, the efficient charge separation that determines the photocatalytic reactivities of these materials is quite restricted. Herein, a judicious combination of piezoelectric and photocatalytic performances of BiOX/BaTiO3 (X = Cl, Br, Cl0.166 Br0.834 ) to enable a high piezophotocatalytic activity is demonstrated. Under the synergic advantages of chemical potential difference and piezoelectric potential difference in BiOX/BaTiO3 composites, the photoinduced carriers recombination is largely halted, which directly contributes to the significantly promoted piezophotocatalytic activity of piezoelectric composites. Inspiringly, the BiOBr/BaTiO3 composites under light irradiation with auxiliary ultrasonic activation result in an ultrahigh and stable photocatalytic performance, which is much higher than the total of those by isolated photocatalysis and piezocatalysis, and can rival current excellent photocatalytic system. In fact, the theoretical piezoelectric potential difference of BiOBr/BaTiO3 composites reaches 100 mV, which far exceeds the pure BaTiO3 of 31.21 mV and BiOBr of 30 mV, respectively. First, fabrication of BiOX/BaTiO3 piezoelectric composites and its remarkable piezophoto coupling catalysis behavior lays new ground for developing high-efficiency piezoelectric photocatalysts in purifying wastewater, killing bacteria, and other piezophototronic processes.
Keywords: built-in electric fields; photocatalysis; piezoelectric composites; piezophototronic effect; polarization.
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