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Keywords = sillenite

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22 pages, 6261 KB  
Article
The Development of a New Bi12ZnO20/AgI Heterosystem for the Degradation of Dye-Contaminated Water by Photocatalysis Under Solar Irradiation: Synthesis, Characterization and Kinetics
by Serine Madji, Mohamed Belmedani, Elhadj Mekatel, Sarra Zouaoui and Seif El Islam Lebouachera
Processes 2025, 13(5), 1342; https://doi.org/10.3390/pr13051342 - 27 Apr 2025
Cited by 2 | Viewed by 1019
Abstract
This study explores the efficiency of heterogeneous photocatalysis in wastewater treatment, which is recognized for inducing significant rates of degradation and mineralization of various contaminants, including dyes. The study focuses on the development of an innovative composite via a combination of the sillenite [...] Read more.
This study explores the efficiency of heterogeneous photocatalysis in wastewater treatment, which is recognized for inducing significant rates of degradation and mineralization of various contaminants, including dyes. The study focuses on the development of an innovative composite via a combination of the sillenite type semiconductor Bi12ZnO20 and the halide-type semiconductor AgI. Both semiconductors were synthesized via co-precipitation, and their phases were identified using X-ray diffraction and characterized by scanning electron microscopy, Raman spectroscopy, Brunauer–Emmett–Teller analysis for specific surface area, UV–Visible diffuse reflectance spectroscopy, and the point of zero charge. The evaluation of the photocatalytic activity of the Bi12ZnO20/AgI heterosystem was carried out by monitoring the degradation process of Basic Blue 41 (BB41) under solar irradiation conditions. The results of this study revealed that the Bi12ZnO20/AgI heterosystem achieved the efficient degradation of BB41, with a removal rate of 98% after 150 min of treatment. The mineralization study showed that the TOC value decreased from 19.89 mg L−1 to 6.87 mg L−1, indicating that a significant portion of BB41 was mineralized. Via kinetic research, it was established that the degradation process followed a pseudo-first-order mechanism. Furthermore, recycling tests showed that the synthesized heterostructures maintained good structural stability and acceptable reusability over several cycles. These findings highlight the potential of heterogeneous photocatalysis as a promising approach to addressing environmental challenges associated with azo dyes. Full article
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11 pages, 3445 KB  
Article
Exploring the Synthesis of Novel Sillenite Bi12SnO20: Effect of Calcination Temperature on the Phase Formation and Catalytic Performance
by Oussama Baaloudj, Hamza Kenfoud, Monica Brienza, Atef El Jery, Moutaz Aldrdery and Aymen Amin Assadi
Catalysts 2024, 14(9), 650; https://doi.org/10.3390/catal14090650 - 23 Sep 2024
Viewed by 1912
Abstract
Sillenite materials have been the focus of intense research in recent years due to their unique properties and distinct structure with the I23 space group. This electronic structure has reflected high-quality applications and results for some environmental processes such as photocatalysis. This paper [...] Read more.
Sillenite materials have been the focus of intense research in recent years due to their unique properties and distinct structure with the I23 space group. This electronic structure has reflected high-quality applications and results for some environmental processes such as photocatalysis. This paper investigates the synthesis of a new sillenite, Bi12SnO20, and its characteristics, emphasizing its potential for photocatalytic applications. The sillenite Bi12SnO20 has been synthesized through the co-precipitation method by mixing the appropriate ratio of Bi and Sn ions. The obtained particles after precipitation and drying were characterized by thermogravimetric analysis (TGA) and then calcined at different temperatures based on this analysis. The phase has been identified by structural analysis using X-ray diffraction (XRD), and its morphology after identification was carried out by scanning electron microscopy (SEM). The calcination temperature has been found to have a critical role in obtaining the phase, where the phase was found to be formed at temperatures between 310 and 400 °C and changed to other phases within higher temperatures. The physicochemical properties of this sillenite were also studied by Fourier-transform infrared spectroscopy (FTIR) and UV Visible Spectrometer (UV-Vis). To study the obtained phases at different calcination temperatures, performance testing was performed under visible light to remove different contaminants, which are Tetracycline, Bisphenol A, and Rhodamine B. The phase Bi12SnO20 obtained at 350 °C with a catalyst dose of 1 g/L showed the highest performance for removing these pollutants with concentrations of 20 mg/L, with an efficiency of almost 100% within 2 h. This work will be useful as an important resource and strategy for the development of this sillenite material in its pure phase. Full article
(This article belongs to the Special Issue Catalytic Energy Conversion and Catalytic Environmental Purification)
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11 pages, 3188 KB  
Article
Synthesis and Characterization of Iron–Sillenite for Application as an XRD/MRI Dual-Contrast Agent
by Diana Vistorskaja, Jen-Chang Yang, Yu-Tzu Wu, Liang-Yu Chang, Po-Wen Lu, Aleksej Zarkov, Inga Grigoraviciute and Aivaras Kareiva
Crystals 2024, 14(8), 706; https://doi.org/10.3390/cryst14080706 - 5 Aug 2024
Viewed by 1367
Abstract
In the present work, iron–sillenite (Bi25FeO40) was synthesized using a simple solid-state reaction method and characterized. The effects of the synthesis conditions on the phase purity of Bi2O3/Fe3O4, morphological features, and [...] Read more.
In the present work, iron–sillenite (Bi25FeO40) was synthesized using a simple solid-state reaction method and characterized. The effects of the synthesis conditions on the phase purity of Bi2O3/Fe3O4, morphological features, and possible application as an XRD/MRI dual-contrast agent were investigated. For the synthesis, the stoichiometric amounts of Bi2O3 and Fe3O4 were mixed and subsequently milled in a planetary ball mill for 10 min with a speed of 300 rpm. The milled mixture was calcined at various temperatures (550 °C, 700 °C, 750 °C, 800 °C, and 850 °C) for 1 h in air at a heating rate of 5 °C/min. For phase identification, powder X-ray diffraction (XRD) analysis was performed and infrared (FTIR) spectra were recorded. The surface morphology of synthesized samples was studied by field-emission scanning electron microscopy (FE-SEM). For the radiopacity measurements, iron–sillenite specimens were synthesized at different temperatures and mixed with different amounts of BaSO4 and Laponite solution. It was demonstrated that iron–sillenite Bi25FeO40 possessed sufficient radiopacity and could be a potential candidate to meet the requirements of its application as an XRD/MRI dual-contrast agent. Full article
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16 pages, 3653 KB  
Article
Photocatalytic Decomposition of Rhodamine B and Selective Oxidation of 5-Hydroxymethylfurfural by β-Bi2O3/Bi12SiO20 Nanocomposites Produced by Laser
by Aleksandra G. Golubovskaya, Tamara S. Kharlamova, Ekaterina A. Gavrilenko, Elena D. Fakhrutdinova, Olga V. Vodyankina, Sergei A. Kulinich and Valery A. Svetlichnyi
J. Compos. Sci. 2024, 8(2), 42; https://doi.org/10.3390/jcs8020042 - 24 Jan 2024
Cited by 9 | Viewed by 2790
Abstract
In this work, we studied the catalytic performance of a β-Bi2O3/Bi12SiO20 nanocomposite material in the reactions involving the photodecomposition of rhodamine B and selective photooxidation of 5-hydroxymethylfurfural (HMF). The semiconductor composite nanomaterial was obtained by means [...] Read more.
In this work, we studied the catalytic performance of a β-Bi2O3/Bi12SiO20 nanocomposite material in the reactions involving the photodecomposition of rhodamine B and selective photooxidation of 5-hydroxymethylfurfural (HMF). The semiconductor composite nanomaterial was obtained by means of the mechanical grinding of a mixture of nanopowders of β-Bi2O3 and sillenite, both individually produced via pulsed laser ablation. The crystal structure of the prepared composite particles was confirmed by means of X-ray diffraction, while the optical properties of both individual components and their composite (with different ratios of Bi2O3 and Bi12SiO20) were also studied. The photocatalytic activity of the composite particles was studied in the course of their decomposition of rhodamine B under LED excitation at wavelengths of 375, 410 and 470 nm. It was shown that the optimal β-Bi2O3/Bi12SiO20 ratio in the composite particles resulted in their photocatalytic activity exceeding those of both single-phase β-Bi2O3 and Bi12SiO20, as well as that of their mixtures (by ~2.3 times for the excitation of an LED with λ = 375 nm). The novel composite particles were also found to perform better in the selective photocatalytic oxidation of HMF: at a conversion of ~5%, the selectivity toward DFF of the nanocomposite was significantly higher (10.3%) than that of sample Bi2O3 (−4.2%). A model was proposed that explains the increase in activity of the newly prepared photocatalyst due to the formation of a type II heterojunction in its particles. Full article
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14 pages, 3894 KB  
Article
A Comparative Study of Eu3+-Doped Sillenites: Bi12SiO20 (BSO) and Bi12GeO20 (BGO)
by Marcin Kowalczyk, Marcin Kaczkan, Andrzej Majchrowski and Michał Malinowski
Materials 2023, 16(4), 1621; https://doi.org/10.3390/ma16041621 - 15 Feb 2023
Cited by 2 | Viewed by 2259
Abstract
The spectroscopic properties of Eu3+-doped Bi12SiO20 (BSO) were investigated and compared with that of Eu3+-doped Bi12GeO20 (BGO). The emission properties and the absorption spectra have been measured at 10 K as well as [...] Read more.
The spectroscopic properties of Eu3+-doped Bi12SiO20 (BSO) were investigated and compared with that of Eu3+-doped Bi12GeO20 (BGO). The emission properties and the absorption spectra have been measured at 10 K as well as at 300 K (room temperature). Luminescence was detected due to the direct excitation of the 5D0 level of Eu3+, as well as through the excitation of the 5D1 level. The Judd–Ofelt theoretical framework was used to compute the radiative lifetimes (τ) and the omega parameters (Ωλ). The electric dipole transition probabilities, asymmetry ratios (R), along with the branching ratios (β) were also determined based on the obtained experimental data. The strongest detected luminescence belongs to the 5D07F0 transition observed at 578 nm, similar to the BGO sillenite. Reasons for the major presence of the 5D07F0 emission, theoretically forbidden by the Judd–Ofelt Theory, were investigated and compared with that of the BGO sillenite. Obtained results showed that the strong 5D07F0 line is also present in Eu:BSO, indicating that this is a feature of the entire sillenite family and not just Eu:BGO. Full article
(This article belongs to the Special Issue Trends in Electronic and Optoelectronic Materials)
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13 pages, 3040 KB  
Article
Polyaniline/Bi12TiO20 Hybrid System for Cefixime Removal by Combining Adsorption and Photocatalytic Degradation
by Oussama Baaloudj, Noureddine Nasrallah, Hamza Kenfoud, Khaled Wassim Bourkeb and Ahmad K. Badawi
ChemEngineering 2023, 7(1), 4; https://doi.org/10.3390/chemengineering7010004 - 10 Jan 2023
Cited by 49 | Viewed by 4004
Abstract
Sillenite catalysts have shown efficient photocatalytic activity for the removal of various pollutants from water in previous studies, thus enhancing their activity by combining them with other materials will be very promising for environmental applications. In this context, an interesting hybrid system containing [...] Read more.
Sillenite catalysts have shown efficient photocatalytic activity for the removal of various pollutants from water in previous studies, thus enhancing their activity by combining them with other materials will be very promising for environmental applications. In this context, an interesting hybrid system containing Polyaniline (PANI) as an adsorbent and Bi12TiO20 (BTO) sillenite as a catalyst was proposed in this work. Cefixime (CFX) has been selected as a pollutant for this study, and its removal was evaluated using PANI (adsorption), PANI and BTO (combined system) and the hybrid system Bi12TiO20/Polyaniline (BTO/PANI). First, the impact of PANI adsorption was investigated on its own; after that, the solution was filtered to separate the adsorbent from the liquid in order to re-treat the solution using photocatalysis (combining adsorption with photocatalysis). At the same time, a similar technique was used involving the hybrid system BTO/PANI. The results show that the hybrid system can remove a very high Cefixime concentration of 30 mg/L, almost 100%, within only 2 h, and this is better than previous investigations. These results indicate that it is possible to combine photocatalysis and adsorption processes to control water pollution. Full article
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13 pages, 2017 KB  
Review
Bismuth Sillenite Crystals as Recent Photocatalysts for Water Treatment and Energy Generation: A Critical Review
by Oussama Baaloudj, Hamza Kenfoud, Ahmad K. Badawi, Achraf Amir Assadi, Atef El Jery, Aymen Amine Assadi and Abdeltif Amrane
Catalysts 2022, 12(5), 500; https://doi.org/10.3390/catal12050500 - 29 Apr 2022
Cited by 49 | Viewed by 4782
Abstract
Photocatalysis has been widely studied for environmental applications and water treatment as one of the advanced oxidation processes (AOPs). Among semiconductors that have been employed as catalysts in photocatalytic applications, bismuth sillenite crystals have gained a great deal of interest in recent years [...] Read more.
Photocatalysis has been widely studied for environmental applications and water treatment as one of the advanced oxidation processes (AOPs). Among semiconductors that have been employed as catalysts in photocatalytic applications, bismuth sillenite crystals have gained a great deal of interest in recent years due to their exceptional characteristics, and to date, several sillenite material systems have been developed and their applications in photoactivity are under study. In this review paper, recent studies on the use of Bi-based sillenites for water treatment have been compiled and discussed. This review also describes the properties of Bi-based sillenite crystals and their advantages in the photocatalytic process. Various strategies used to improve photocatalytic performance are also reviewed and discussed, focusing on the specific advantages and challenges presented by sillenite-based photocatalysts. Furthermore, a critical point of certain bismuth catalysts in the literature that were found to be different from that reported and correspond to the sillenite form has also been reviewed. The effectiveness of some sillenites for environmental applications has been compared, and it has demonstrated that the activity of sillenites varies depending on the metal from which they were produced. Based on the reviewed literature, this review summarizes the current status of work with binary sillenite and provides useful insights for its future development, and it can be suggested that Bismuth sillenite crystals can be promising photocatalysts for water treatment, especially for degrading and reducing organic and inorganic contaminants. Our final review focus will emphasize the prospects and challenges of using those photocatalysts for environmental remediation and renewable energy applications. Full article
(This article belongs to the Special Issue Environmental Catalysis for Air Pollution Applications)
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11 pages, 2491 KB  
Article
Structural and Optical Properties of Bi12NiO19 Sillenite Crystals: Application for the Removal of Basic Blue 41 from Wastewater
by Billal Brahimi, Hamza Kenfoud, Yasmine Benrighi and Oussama Baaloudj
Photochem 2021, 1(3), 319-329; https://doi.org/10.3390/photochem1030020 - 27 Sep 2021
Cited by 12 | Viewed by 3713
Abstract
This article covers the structural and optical property analysis of the sillenite Bi12NiO19 (BNO) in order to characterize a new catalyst that could be used for environmental applications. BNO crystals were produced by the combustion method using Polyvinylpyrrolidone as a [...] Read more.
This article covers the structural and optical property analysis of the sillenite Bi12NiO19 (BNO) in order to characterize a new catalyst that could be used for environmental applications. BNO crystals were produced by the combustion method using Polyvinylpyrrolidone as a combustion reagent. Different approaches were used to characterize the resulting catalyst. Starting with X-ray diffraction (XRD), the structure was refined from XRD data using the Rietveld method and then the structural form of this sillenite was illustrated for the first time. This catalyst has a space group of I23 with a lattice parameter of a = 10.24 Å. In addition, the special surface area (SSA) of BNO was determined by the Brunauer-Emmett-Teller (BET) method. It was found in the range between 14.56 and 20.56 cm2·g−1. Then, the morphology of the nanoparticles was visualized by Scanning Electron Microscope (SEM). For the optical properties of BNO, UV-VIS diffusion reflectance spectroscopy (DRS) was used, and a 2.1 eV optical bandgap was discovered. This sillenite′s narrow bandgap makes it an effective catalyst for environmental applications. The photocatalytic performance of the synthesized Bi12NiO19 was examined for the degradation of Basic blue 41. The degradation efficiency of BB41 achieved 98% within just 180 min at pH ~9 and with a catalyst dose of 1 g/L under visible irradiation. The relevant reaction mechanism and pathways were also proposed in this work. Full article
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17 pages, 5234 KB  
Article
Application of Bi12ZnO20 Sillenite as an Efficient Photocatalyst for Wastewater Treatment: Removal of Both Organic and Inorganic Compounds
by Oussama Baaloudj, Noureddine Nasrallah, Hamza Kenfoud, Faisal Algethami, Abueliz Modwi, Ahlem Guesmi, Aymen Amine Assadi and Lotfi Khezami
Materials 2021, 14(18), 5409; https://doi.org/10.3390/ma14185409 - 18 Sep 2021
Cited by 26 | Viewed by 3652
Abstract
This work aims to synthesize and characterize a material that can be used as an effective catalyst for photocatalytic application to remove both organic and inorganic compounds from wastewater. In this context, sillenite Bi12ZnO20 (BZO) in a pure phase was [...] Read more.
This work aims to synthesize and characterize a material that can be used as an effective catalyst for photocatalytic application to remove both organic and inorganic compounds from wastewater. In this context, sillenite Bi12ZnO20 (BZO) in a pure phase was synthesized using the sol–gel method. Before calcination, differential scanning calorimetry (DSC) analysis was done to determine the temperature of the formation of the sillenite phase, which was found to be 800 °C. After calcination, the phase was identified by X-ray diffraction (XRD) and then refined using the Rietveld refinement technique. The results prove that BZO crystals have a cubic symmetry with the space group I23 (N°197); the lattice parameters of the structure were also determined. From the crystalline size, the surface area was estimated using the Brunauer-Emmett-Teller (BET) method, which was found to be 11.22 m2/g. The formation of sillenite was also checked using the Raman technique. The morphology of the crystals was visualized using electron scanning microscope (SEM) analysis. After that, the optical properties of BZO were investigated by diffuse reflectance spectroscopy (DRS) and photoluminescence (PL); an optical gap of 2.9 eV was found. In the final step, the photocatalytic activity of the BZO crystals was evaluated for the removal of inorganic and organic pollutants, namely hexavalent chromium Cr(VI) and Cefixime (CFX). An efficient removal rate was achieved for both contaminants within only 3 h, with a 94.34% degradation rate for CFX and a 77.19% reduction rate for Cr(VI). Additionally, a kinetic study was carried out using a first-order model, and the results showed that the kinetic properties are compatible with this model. According to these findings, we can conclude that the sillenite BZO can be used as an efficient photocatalyst for wastewater treatment by eliminating both organic and inorganic compounds. Full article
(This article belongs to the Special Issue Advances in Functional Nanomaterials for Environmental Applications)
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50 pages, 6084 KB  
Review
Peculiar Structural Effects in Pure and Doped Functional Single Crystals of Complex Compositions
by Galina Kuz’micheva and Irina Kaurova
Molecules 2020, 25(10), 2451; https://doi.org/10.3390/molecules25102451 - 25 May 2020
Cited by 6 | Viewed by 5116
Abstract
Results of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The [...] Read more.
Results of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The reasons for the coloration of the crystals are explained. A change in crystal symmetry due to crystal–chemical and growth reasons is considered. The use of structural analysis and X-ray absorption spectroscopy is substantiated to reveal the role of activator ions in the formation of statistical and local structures, respectively. A relationship between the distribution of activator ions over crystallographic sites and photoluminescent parameters of materials is established, which allows selecting optimal systems for the application. The combined results of studying single-crystal compounds of other classes (huntite, sillenite, whitlockite, garnet, tetragonal bronzes) allow formulating and summarizing structural effects that appeared in the systems and caused by various factors and, in many cases, due to the local environment of cations. A principal difference in the structural behavior of solid solutions and doped compounds is shown. The methodology developed for single-crystal samples of complex compositions can be recommended for the systematic structural studies of functional materials of different compositions. Full article
(This article belongs to the Special Issue Crystallography and Crystal Chemistry)
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14 pages, 3796 KB  
Article
Optical Investigation of Eu3+ Doped Bi12GeO20 (BGO) Crystals
by M. Kowalczyk, T.F. Ramazanova, V.D. Grigoryeva, V.N. Shlegel, M. Kaczkan, B. Fetliński and M. Malinowski
Crystals 2020, 10(4), 285; https://doi.org/10.3390/cryst10040285 - 9 Apr 2020
Cited by 16 | Viewed by 8945
Abstract
The spectroscopic properties of Eu3+ doped Bi12GeO20 (BGO) sillenite bulk crystals that were grown by the low-thermal-gradient Czochralski technique (LTG Cz) were investigated. The absorption spectra and the emission properties have been measured at room temperature (300 K) and [...] Read more.
The spectroscopic properties of Eu3+ doped Bi12GeO20 (BGO) sillenite bulk crystals that were grown by the low-thermal-gradient Czochralski technique (LTG Cz) were investigated. The absorption spectra and the emission properties have been measured at room temperature (300 K) and at 10 K. Luminescence was observed both due to the direct Eu3+ ion excitation, as well as under UV excitation due to the energy transfer between Bi3+ and Eu3+ ions. Bi3+ → Eu3+ energy transfer mechanisms in Eu3+:BGO doped host were investigated. The Ωλ parameters, as well as radiative lifetimes, were calculated based upon the Judd-Ofelt formalism. The branching ratios and electric dipole transition probabilities were also determined, based upon the obtained experimental results. Luminescence has been observed from the 5D0,1,2 levels of Eu3+, with emissions from the 5D0 level being the strongest. The strongest observed luminescence band corresponds to the 5D07F0 transition at 578.7 nm. Reasons for the strong presence of the theoretically forbidden 5D07F0 emission were investigated. Full article
(This article belongs to the Special Issue Rare Earths-Doped Materials)
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11 pages, 879 KB  
Article
Orientation and Temperature Dependence of Piezoelectric Properties for Sillenite-Type Bi12TiO20 and Bi12SiO20 Single Crystals
by Chuanying Shen, Huaijin Zhang, Yuanyuan Zhang, Honghao Xu, Haohai Yu, Jiyang Wang and Shujun Zhang
Crystals 2014, 4(2), 141-151; https://doi.org/10.3390/cryst4020141 - 20 Jun 2014
Cited by 20 | Viewed by 8946
Abstract
The full matrix of electro-elastic constants of sillenite-type crystals Bi12TiO20 (BTO) and Bi12SiO20 (BSO) were determined by the resonance method, with d14 and k14 being on the order of 40–48 pC/N and 31%–36%, respectively. In [...] Read more.
The full matrix of electro-elastic constants of sillenite-type crystals Bi12TiO20 (BTO) and Bi12SiO20 (BSO) were determined by the resonance method, with d14 and k14 being on the order of 40–48 pC/N and 31%–36%, respectively. In addition, double-rotated orientation dependence of d33 was investigated, with the maximum values of 25–28 pC/N being achieved in ZXtl45°/54°-cut samples. The electrical resistivity of BSO was found to be two orders higher than that of BTO, being on the order of 7 × 105 Ω cm at 500 °C. The temperature dependence of dielectric and piezoelectric properties were investigated. BSO exhibited a high thermal stability in the temperature range of 25–500 °C, while BTO showed a variation of ~3% in the range of 25–350 °C. The high values of d14 and k14, together with the good thermal stability, make BTO and BSO crystals potential candidates for electromechanical applications in medium temperature range. Full article
(This article belongs to the Special Issue Piezoelectric Crystals)
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