Superior photo-piezoelectric catalytic performance using Bi0.5Na0.5TiO3@BiVO4 based cloth

Piezoelectric materials were proven as a promising candidate to improve the efficiency of photocatalysis degradation activity via preventing the recombination of photoelectron-holes by stress-induced electric potential. In this work, core-shell structured catalytic agents consisting of lead-free piezoelectric ceramics Bi0.5Na0.5TiO3 (BNT) and photoelectric materials BiVO4 (BVO) were prepared by a hydrothermal method. The BNT@BVO powders were employed in the degradation of organic dye Rhodamine B (RhB) and exhibited superior catalytic activity due to the piezo-photoelectronic coupling effect. High first-order rate constants k of 0.110 min(-1) and 0.045 min(-1) were achieved for RhB solution with the initial concentrations of C-0 = 5 mg L-1 and 10 mg L-1, respectively. To overcome the difficulties of powder recovery in applications, a series of macroscopic cloths with different BNT@BVO filler loadings and thicknesses were fabricated via an electrostatic spinning route. The degradation efficiency of RhB solution (C-0 = 10 mg L-1) by a piece of BNT@BVO cloth (similar to 50 cm(2)) reached 80% in 100 min with a first-order rate constant of 0.015 min(-1). In order to reveal the charge transfer mechanism in the interface layer between piezoelectric materials and photoelectric materials, a series of photoelectrochemical measurements were carried out. The conduction band (CB) position of BNT was bent from -1.1 eV towards -0.8 eV after being coated with BVO, which means less energy was required to be absorbed for the charge transition from the valence band (VB) to CB for the BNT and BNT@BVO have the same VB, resulting in a higher electron-hole separation efficiency. The enhancement of current density after coating with BVO from 2.3 mu A cm(-2) to 4.9 mu A cm(-2) (about 110% higher than that of pure BNT) at a potential of 1.23 V (vs. RHE) further verifies that the coupling between BNT and BVO has significant influence on charge separation efficiency.

Automated summary

Piezoelectric materials have been shown to enhance the efficiency of photocatalytic degradation by preventing electron-hole recombination, as demonstrated in the core-shell structured catalytic agents consisting of lead-free piezoelectric ceramics BNT and photoelectric materials BVO. The BNT@BVO powders exhibited superior catalytic activity in degrading the organic dye RhB, with the macroscopic cloths fabricated for practical applications. Photoelectrochemical measurements showed the significant influence of the coupling between BNT and BVO on charge separation efficiency, leading to higher electron-hole separation efficiency and enhanced current density.