Boosting piezocatalytic performance of perovskite BiFeO3 with controlled oxygen vacancies

Piezocatalysis, which is capable of directly converting mechanical energy into chemical energy, has been identified as a promising strategy for environmental wastewater remediation and clean energy production. Regrettably, the present piezocatalysis is still in the early stage and the piezocatalytic activity is still far from ideal. Thus, exploring and discovering more efficient catalyst design strategies remains a challenge. In this work, a novel and simple method was employed to synthesize a piezocatalytic BiFeO3 (BFO) using metal-organic frameworks (MOFs) as precursors, and the MOFs derived BFO (MOF-BFO) has excellent piezocatalytic activity. The maximum reaction rate constant (k) for rhodamine B (RhB) can reach 1.70 x 10-2 min- 1, which is about 4.7 times that of the sample annealed at 700 degrees C (BFO-700, 0.36 x 10-2 min- 1) and about 10.3 times that of the sample annealed at 450 degrees C (BFO-450, 0.17 x 10-2 min- 1) using conventional one pot co-precipitation method. The MOF-BFO catalyst is also suitable for degradation of other typical dyes, including methylene blue (MB) and methyl orange (MO), dramatically increasing its utility against complex wastewater components. What's more, the analysis indicates that the concentration of oxygen vacancy (OV) may be the primary factor influencing the piezocatalytic performance. Thus, the effect of OV concentration on piezocatalytic activity is further studied, which acts like a double-edged sword, manifesting that creating moderate OV is crucial for regulating piezocatalytic performance. This study not only demonstrates the potential of MOF-BFO as a candidate material for piezocatalytic applications, but also offers insights for the development of efficient piezocatalysts in future.