Abstract:The solid-phase method was used to synthesize NaNbO₃ micropowders, the hydrothermal method was used to synthesize NaNbO₃ nanowires, and the molten salt method was used to synthesize NaNbO₃ microsheets. The piezoelectric catalytic efficiency of NaNbO₃ with three different morphologies was compared, and the factors affecting the catalytic efficiency were explored. Under the same catalytic conditions, NaNbO₃ micropowders, NaNbO₃ nanowires and NaNbO₃ microsheets degrade 92.4%, 57.9% and 92.3% of RhB within 30 min, respectively, and the corresponding reaction rate constants k are 0.08893 min^-1, 0.02723 min^-1 and 0.08013 min^-1, respectively. Unlike the nanowires and nanosheets in the literature, which have better catalytic performance due to their easier deformation, the NaNbO₃ micropowders in this paper exhibit the best piezoelectric catalytic performance. After research, it is found that NaNbO₃ micronpowders and NaNbO₃ microsheets obtained higher crystallinity after high temperature treatment, and the catalytic effect was better. Among them, the NaNbO₃ micronpowder has a larger specific surface area, which is about 3 times of that of the micronsheets, and the reaction rate constant k is only 1.1 times that of the micronsheets. The easily deformable nanowires have the worst catalytic effect due to their low crystallinity. Based on the above factors, the main factors affecting the catalytic effect are crystallinity, specific surface area, and morphology. Which factors play a leading role must be fully analyzed.

Key words: NaNbO₃; morphology control; piezoelectric catalysis; crystallinity; piezoelectric potential; specific surface area