Piezo/pyro/photo‐catalysis activities in Ba_0.85Ca_0.15(Ti_0.9Zr_0.1)_1‐xFe_xO₃ ceramics

Abstract

Ba 0.85 Ca 0.15 (Ti 0.9 Zr 0.1) 1-x Fe x O 3 (x = 0, 0.5, and 1%) ceramics were studied for piezocatalysis, photocatalysis, and pyrocatalysis using dye degradation in the simulated wastewater. The effect of electrical poling was also performed and found a significant impact of poling on all three catalytic reactions. Fe decreased the optical bandgap of Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZTO) to the visible region. Bandgap for x = 0, 0.005, and 0.01 was found to be 3.14 eV, 2.75 eV, and 2.61 eV, respectively. Interestingly, visible light photocatalytic activity was observed after Fe inclusion in BCZTO lattice. These compositions have also demonstrated dye degradation under ultrasonication (piezocatalytsis) and during temporal temperature change (pyrocatalysis). Results indicate promising multicatalysis in BCZTO ceramics which can be tuned using Fe substitution. K E Y W O R D S ferroelectric, multicatalysis, photocatalysis, piezocatalysis, piezoelectric, pyrocatalysis 46 | SHARMA And VAISH From the above-mentioned discussion, it is clear that catalytic reactions can be triggered using ambient mechanical vibrations, thermal energy, or photons. If one material can demonstrate all these catalysis phenomena (piezocatalysis, pyrocatalysis, and photocatalysis), it can be a more effective, versatile, and multifunctional utility. This could be possible after the tuning bandgap of piezoelectric semiconductors. To attempt in the direction of multicatalysis, BCZTO was selected in the present study. BCZTO is a famous piezoelectric material. It has been reported for many piezo/pyro/ferroelectric related applications. 10 To create visible light photocatalytic activity in the BCZTO, Fe +3 (accepter) doping was done in the BCZTO. Such acceptor doping may create vacancies defects and reduce the effective bandgap. In the recent past, Fe was doped in various BaTiO 3 based ceramics for achieving various physical properties such as multiferroic characteristics. Fe substitution decreases tetragonality in BCZTO which was reflected from X-ray diffraction data along with dielectric behavior. 36 Moreover, the ferro-para phase transition was diffused after Fe doping which indicates the breaking of long-range interaction of ferroelectric domains to defects created by Fe. Such relaxer-like behavior was also noticed in an another article where Fe doping could also increase electrostrictive coefficients of the BCZTO. 37 There are few more reports where Fe doping could increase electrocaloric and other electrical properties in BCZTO. 38,39 Fe doping was also well explored in BaTiO 3 ceramics for various viewpoints. 40-46 BCZTO was reported for UV light active photocatalyst. 10 Fe doping can reduce its bandgap for visible light activation of the BCZTO and hence Fe was introduced in the BCZTO as Ba 0.85 Ca 0.15 (Ti 0.9 Zr 0.1) 1-x Fe x O 3. Finally, piezocatalysis, pyrocatalysis, and photocatalysis performance were examined and reported in the subsequent sections.

Engineering the Defects and Microstructures in Ferroelectrics for Enhanced/Novel Properties: An Emerging Way to Cope with Energy Crisis and Environmental Pollution

“…The high interfacial energy at MPB can drive the coupling between the local polar defect heterogeneities and ferroelectric polarization, leading to defect‐induced gap‐states whilst maintaining high piezoelectricity (Figure 9d). [ 35,91–94 ] Sharma and Vaish [ 95 ] reported a bandgap engineered Ba 0.85 Ca 0.15 (Ti 0.9 Zr 0.1 ) 1‐ x Fe x O 3 ceramic with a low bandgap of 2.61 eV, and achieved piezo/pyro/photocatalytic activities, which validates the triple‐state multiple catalysts behavior of ferroelectric materials.…”

“…[ 117 ] Compared with microscale KN‐BNZ particles, the research on the catalytic performance of the nanoscale particles is highly expected. Sharma and Vaish [ 95 ] successfully prepared Fe doped Ba 0.85 Ca 0.15 (Ti 0.9 Zr0.1) 1‐ x Fe x O 3 and engineered the bandgap from 3.14 to 2.61 eV via SSR. Though Fe doping can induce substantial piezo/pyro/photocatalytic activities, the ceramic form has greatly limited the multicatalytic performance due to its small surface area.…”

“…The combination of photocatalysis, piezocatalysis, and pyrocatalysis will be an interesting topic in the future given that defect engineering can tune the bandgap, piezoelectricity, and T C . Recently, Sharma and Vaish [ 95 ] did a pioneer work in this field by using Fe doped Ba 0.85 Ca 0.15 (Ti 0.9 Zr 0.1 ) 1‐ x Fe x O 3 ceramics. It is found that though the doping of Fe in the composition can enlarge the absorption ( Figure a), the piezoelectricity decreases as doping level increases (Figure 50b).…”

Pyro-catalysis for tooth whitening via oral temperature fluctuation

“…The basic working principle of pyro-catalysis is similar to that of photo-catalysis and piezo-catalysis, i.e., generation of ROS in response to the external stimuli, but the stimuli of pyro-catalysts are temperature fluctuations, rather than the light or mechanical vibration for photo- and piezo-catalysts. Although the pyro-catalysis and photo-catalysis exhibit the same electrochemical-redox process 29 – 31 , the pyro-catalysis has drawn less technological attention relative to photo-catalysis due to its power-based temperature fluctuation stimuli.…”

Effect of poling on piezocatalytic removal of muti‐pollutants using BaTiO3

“…[10][11][12] Most of the recent studies have reported piezocatalysis using BaTiO 3 , Sr 0.7 Ba 0.3 Nb 2 O 6 , Bi 4 Ti 3 O 12 , LiNbO 3 , K 0.5 Na 0.5 NbO 3 , Bi 0.5 Na 0.5 TiO 3, Pb(Zr,Ti)O 3 , Ba 0.85 Ca 0.85 Ti 0.90 Zr 0.10 O 3 (BCZTO), and ZnO. [13][14][15][16][17][18][19][20][21] Among these, BaTiO 3 is the simplest, traditional, and important ferroelctric ceramics. It has been well explored for various physical and chemical modifications.…”