Bismuth Ferrite Nanocylinders Decorated with Graphene Quantum Dots for Enhanced Piezocatalysis

The nano-scale size and morphology of the piezoelectric material affect the piezoelectric properties related to the degree of lattice distortion. Herein, cylinder-like bismuth ferrite (BiFeO₃) with an average diameter of 100 nm is prepared and uniformly loaded with graphene quantum dots (GQDs) on the surface. Under ultrasonic vibration, the piezocatalyst with the optimal loading ratio of GQDs (BiFeO₃@GQDs-3%) achieves complete degradation of 10 mg L^-1 BPA within 30 min with the corresponding degradation rate constant of 0.178 min^-1 that is 2.4 times higher than that of undecorated BiFeO₃ nanocylinders. The enhanced piezocatalytic oxidation activity is attributed to the small size of the BiFeO₃ nanocylinders, which have a large piezoelectric potential and a significant lattice distortion under ultrasonic vibration. In addition, the introduction of highly conductive GQDs accelerates the transfer of free electrons, inhibiting the recombination of free electrons and holes, thereby promoting the piezocatalytic reaction. This work demonstrates the two efficient strategies combined for enhanced piezocatalytic activities by promoting lattice distortion through morphology control and accelerating electron transfer with high-conductive quantum dots.