Ferroelectricity and Schottky Heterojunction Engineering in AgNbO₃: A Simultaneous Way of Boosting Piezo-photocatalytic Activity

Abstract

As an efficient and economical way of dealing with organic pollutants, piezo-photocatalysis has attracted great interest. In this work, we demonstrated that ferroelectricity and Schottky heterojunction engineering could significantly enhance the piezo-photocatalytic activity of AgNbO3. The poled 20 mol % K+ doped AgNbO3 disclosed its superior piezo-photocatalytic activity of 0.131 min–1 for 10 mg·L–1 RhB, which is 7.8 times of the pristine one under the condition of illumination only. The designed piezo-photocatalyst also exhibited good piezo-photocatalytic stability after four cycles. These merits are attributed to the built-in electric field associated with the large spontaneous polarization and low coercive field originated from the stable ferroelectric state after ferroelectricity engineering, plus with the electron trapper effect of the in situ precipitated metal Ag particles. Our work not only provides a promising piezo-photocatalyst for degrading organic contaminants but also paves a good way for developing high piezo-photocatalytic activity catalysts.

Piezo-Phototronic Coupling Effect in CuBi2O4/AgNbO3 Z-Scheme Heterojunction for High-Efficiency Decomposition of Organic Dye

“…For direct band gap semiconductors, n is equal to 1, whereas for indirect band gap semiconductors, n is equal to 4. AgNbO 3 37 and CuBi 2 O 4 51 are considered as direct band gap semiconductors. Therefore, according to the (αhv) 2 −hv curves of the samples (Figure 5b), the obtained optical band gaps of AgNbO 3 and CuBi 2 O 4 were 2.81 and 1.82 eV, respectively.…”

“…Moreover, the depolarization electric field originating from the spontaneous polarization of ferroelectrics and the piezoelectric potential generated under stress in ferro-/piezoelectric materials with the piezoelectric effect are also used as the built-in electric field to suppress the recombination of photoinduced carriers in the photocatalyst. Ferroelectric materials with the depolarization electric field and piezoelectric potential have been widely used to boost photocatalytic efficiency. − AgNbO 3 as an antiferroelectric material with a piezoelectric coefficient of 330 pC/N exhibits a stronger piezoelectric response, and enhances the photocatalytic performances of AgNbO 3 by regulating its ferro-/piezoelectric characteristics has been proved to be an important strategy. − However, the limited visible light absorption ability of AgNbO 3 with a wider band gap (∼2.8 eV) hinders further improvement of its photocatalytic degradation performance. Constructing AgNbO 3 and the semiconductor with a narrower band gap to be a heterojunction is a simple and effective strategy to enhance its visible light absorption ability, and this heterojunction photocatalyst with suitable energy band matching is expected to achieve enhanced carrier separation ability.…”

Bifunctional defect mediated direct Z-scheme g-C3N4−x/Bi2O3−yheterostructures with enhanced piezo-photocatalytic properties for efficient tooth whitening and biofilm eradication

“…17 Luo et al reported Ag nanoparticle/K + doped AgNbO 3 Schottky heterojunctions, which revealed an improved separation efficiency of electrons and holes and demonstrated outstanding piezo-photocatalytic activities in pollution degradation. 18 Recently, direct Z scheme heterostructures have begun to receive increasing attention in photocatalytic fields due to the improved separation efficiency of carriers and simultaneously maximized redox capability. 14 After the formation of direct Z scheme heterostructures, the photogenerated electrons and holes can be enriched on the semiconductor with a higher reduction and oxidation ability, respectively.…”

Enhanced Piezo‐photocatalytic Performances of AgNbO3 Materials for Dye Decomposition Via Polarization Engineering

“…The piezo-photocatalytic activity of the poled Ag/Ag 0.8 K 0.2 NbO 3 Schottky heterojunction for RhB was 7.8 times of the pristine AgNbO 3 under only illumination. [25] The formation of the interfacial electric field can be accelerated by constructing the Ag 2 O/AgNbO 3 p-n heterojunction, which enhances the separation of photogenerated electron-hole pairs, resulting in a high degradation rate of 95.4 % within 90 minutes for RhB. [26] Some metal cations (such as Bi 3 + , [27] La 3 + [15] at A sites, and Zr 4 + [28,29] at B sites) and LiTaO 3 [30] were introduced into AgNbO 3 to improve its photocatalytic activity.…”