Efficient synthesis of BiFeO3 by the microwave-assisted sol-gel method: 'A' site influence on the photoelectrochemical activity of perovskites
| Autor: | Mehdi Ebadi, Mateusz Trochowski, Wojciech Macyk, Dheerendra Singh, M. Barış Yağcı, Taymaz Tabari |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Band gap Analytical chemistry General Physics and Astronomy 02 engineering and technology Surfaces and Interfaces General Chemistry Crystal structure 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films Dielectric spectroscopy X-ray photoelectron spectroscopy Linear sweep voltammetry Photocatalysis Temperature-programmed reduction 0210 nano-technology Sol-gel |
| Zdroj: | Applied Surface Science. 471:1017-1027 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/j.apsusc.2018.12.082 |
| Popis: | BiFeO3 (BF) and LaFeO3 (LF) perovskites were synthesized using a microwave-assisted (MW) and sol-gel (SG) methods. XRD, XPS, TEM, UV-DRS techniques were applied to study physicochemical properties of perovskites. In addition, Incident Photon-to-Current Efficiency (IPCE) measurements, Linear Sweep Voltammetry (LSV) and impedance spectroscopy were used to characterize electrochemical properties of the materials. The band gap energy increases in the following way: BF-MW (2.05 eV), LF-MW (2.18 eV), BF-SG (2.26 eV) and LF-SG (2.54 eV), demonstrating a remarkable influence of the synthesis method on the optical and electronic properties of the materials. Furthermore, XRD showed a significant impact of the synthesis methods on the crystal structure. Perovskites synthesized under MW irradiation showed a pure crystal structure compared to the perovskites prepared by SG method, which contained some admixtures. IPCE shows that LF-MW has a better charge separation ability compared to BF-MW. However, BF-SG showed the highest activity. Temperature programmed reduction tests (TPR) revealed a better ability of BF-MW to adsorb/desorb oxygen, compared to LF-MW. XPS measurements pointed at the presence of Fe4+. Finally, the photocatalytic activity of the perovskites was tested in solar water-splitting as a function of the synthesis method and presence of Bi and La in “A” sites of the ABO3 perovskites. We postulate, that the Jahn-Teller distortion effect in LF-MW increases its catalytic activity by decreasing the binding energy compared to BF-MW. |
| Databáze: | OpenAIRE |
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