Coupling of piezocatalysis and photocatalysis for efficient degradation of methylene blue by Bi 0.9 Gd 0.07 La 0.03 FeO 3 nanotubes

Photocatalytic degradation of organic pollutants is of great significance for wastewater remediation but is still hindered by the poor catalytic efficiency of the catalysts. Herein, we report a strategy to simultaneously introduce piezocatalysis and to enhance the intrinsic photocatalysis in a single catalyst, which improved the performance for catalytic degradation of methylene blue (MB) significantly. Specifically, piezoelectric BiFeO 3 (BFO) nanotube doped with different contents of Gd and La (Bi 0.9 (Gd x La 1− x ) 0.1 FeO 3 ) were produced by electrospinning. The doping led to a higher concentration of surface oxygen vacancy (OV) in Bi 0.9 Gd 0.07 La 0.03 FeO 3 , which effectively increased the piezoelectric field due to the deformation of BFO, and suppressed the recombination of photon-generated electron-hole pairs. The Bi 0.9 Gd 0.07 La 0.03 FeO 3 nanotube showed excellent catalytic performance under simultaneous light irradiation and ultrasonic excitation, giving an extraordinary 95% degradation of MB within 90 min. These findings suggest that the piezoelectric effect combined with defect engineering can enhance the catalytic performance of Bi 0.9 Gd 0.07 La 0.03 FeO 3 nanotube. This could potentially be extended to other catalytic systems for high-performance pollutant treatment.