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Jyoti S, Vijay A, Terranova U, Gupta SK, Sudarshan K, Vaidya S. Electrocatalytic OER behavior of the Bi-Fe-O system: an understanding from the perspective of the presence of oxygen vacancies. Phys Chem Chem Phys 2024; 26:17324-17333. [PMID: 38860439 DOI: 10.1039/d4cp00348a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
This study aims to understand and correlate the role of the nature and relative concentration of oxygen vacancies with the trend observed in the OER with the Bi-Fe-O system. To understand this, we first investigated the system of oxides using X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR), which revealed the presence of oxygen vacancies in the system. Density functional theory (DFT) was employed to investigate the relative concentration of these vacancies by calculating their formation energies. Positron annihilation lifetime spectroscopy (PALS) was carried out to understand the nature of these oxygen vacancies. We observed that the presence of a higher concentration of monovacancies created due to the absence of oxygen from the structure of Bi2Fe4O9 was mainly responsible for the high performance of the oxide towards the OER compared to that of the other oxides viz-BiFeO3 and Bi25FeO40 of the Bi-Fe-O system.
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Affiliation(s)
- Shaswati Jyoti
- Institute of Nano Science and Technology, Knowledge City, Sector 81, Sahibzada Ajit Singh Nagar, Punjab 140306, India.
| | - Aditi Vijay
- Institute of Nano Science and Technology, Knowledge City, Sector 81, Sahibzada Ajit Singh Nagar, Punjab 140306, India.
| | - Umberto Terranova
- Faculty of Medicine and Health Science, Crewe Campus, University of Buckingham, Crewe, CW1 5DU, UK
| | - Santosh K Gupta
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Kathi Sudarshan
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Sonalika Vaidya
- Institute of Nano Science and Technology, Knowledge City, Sector 81, Sahibzada Ajit Singh Nagar, Punjab 140306, India.
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Lomanova NA. Aurivillius Phases Bim + 1Fem – 3Ti3O3m + 3: Synthesis, Structure, and Properties (a Review). RUSS J INORG CHEM+ 2022. [DOI: 10.1134/s0036023622060146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Mathew G, Daniel M, Peramaiah K, Ganesh MR, Neppolian B. Real-time electrochemical quantification of H2O2 in living cancer cells using Bismuth based MOF. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116255] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Visible light photocatalytic activity of TiO2 with carbon-fluorine heteroatoms simultaneously introduced by CF4 plasma. KOREAN J CHEM ENG 2022. [DOI: 10.1007/s11814-022-1128-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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The Effects of Li+ Doping on Structure and Upconversion Luminescent Properties for Bi3.46Ho0.04Yb0.5Ti3O12: xLi Phosphors. CRYSTALS 2021. [DOI: 10.3390/cryst11101220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A series of novel Li+ doped Bi3.46Ho0.04Yb0.5Ti3O12 (BHYTO: xLi, 0 ≤ x ≤ 0.15) upconversion phosphors were prepared through a sol-gel-sintering method. There exist three emission bands centered at 545 nm, 658 nm, and 756 nm in the upconversion emission spectra at 980 nm excitation, corresponding to energy transitions of 5F4/5S2 → 5I8, 5F5 → 5I8 and 5F4/5S2 → 5I7 of Ho3+, and the upconversion emission intensity of BHYTO: 0.05Li is about 2.2 times stronger than that of BHYTO samples. The luminescent lifetime of the strongest emission (545 nm) is in the range of 45.25 to 65.99 μs for the different BHYTO: xLi phosphors. The energy transfers during the upconversion pumping process from Yb3+ to Ho3+ are mainly responsible for all the emissions, each belonging to a double-photon process. Li+ mainly entered into the interspace sites or occupied Bi3+ sites in Bi4Ti3O12 host during the fabrication process according to its dosage, and the possibility is very low for Li+ to take part in the energy transfer process directly due to its lack of matching levels with 4f of Ho3+ and Yb3+. However, Li+ doping can not only increase the size of crystal grains to improve crystallinity through XRD analysis, but also reduced oxygen vacancies to decrease the number of quenching centers through XPS analysis. The improved crystallinity and reduced quenching centers are proposed to be the main causes for the enhanced upconversion luminescence of the Li+ doped BHYTO phosphor.
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Maček Kržmanc M, Daneu N, Čontala A, Santra S, Kamal KM, Likozar B, Spreitzer M. SrTiO 3/Bi 4Ti 3O 12 Nanoheterostructural Platelets Synthesized by Topotactic Epitaxy as Effective Noble-Metal-Free Photocatalysts for pH-Neutral Hydrogen Evolution. ACS APPLIED MATERIALS & INTERFACES 2021; 13:370-381. [PMID: 33351589 PMCID: PMC7871321 DOI: 10.1021/acsami.0c16253] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/09/2020] [Indexed: 06/02/2023]
Abstract
Low-temperature hydrothermal epitaxial growth and topochemical conversion (TC) reactions offer unexploited possibilities for the morphological engineering of heterostructural and non-equilibrium shape (photo)catalyst particles. The hydrothermal epitaxial growth of SrTiO3 on Bi4Ti3O12 platelets is studied as a new route for the formation of novel nanoheterostructural SrTiO3/Bi4Ti3O12 platelets at an intermediate stage or (100)-oriented mesocrystalline SrTiO3 nanoplatelets at the completed stage of the TC reaction. The Bi4Ti3O12 platelets act as a source of Ti(OH)62- species and, at the same time, as a substrate for the epitaxial growth of SrTiO3. The dissolution of the Bi4Ti3O12 platelets proceeds faster from the lateral direction, whereas the epitaxial growth of SrTiO3 occurs on both bismuth-oxide-terminated basal surface planes of the Bi4Ti3O12 platelets. In the progress of the TC reaction, the Bi4Ti3O12 platelet is replaced from the lateral ends toward the interior by SrTiO3, while Bi4Ti3O12 is preserved in the core of the heterostructural platelet. Without any support from noble-metal doping or cocatalysts, the SrTiO3/Bi4Ti3O12 platelets show stable and 15 times higher photocatalytic H2 production (1265 μmol·g-1·h-1; solar-to-hydrogen (STH) efficiency = 0.19%) than commercial SrTiO3 nanopowders (81 μmol·g-1·h-1; STH = 0.012%) in pH-neutral water/methanol solutions. A plausible Z scheme is proposed to describe the charge-transfer mechanism during the photocatalysis.
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Affiliation(s)
- Marjeta Maček Kržmanc
- Advanced
Materials Department, Jožef Stefan
Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Nina Daneu
- Advanced
Materials Department, Jožef Stefan
Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Alja Čontala
- Advanced
Materials Department, Jožef Stefan
Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
- Jožef
Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Saswati Santra
- Advanced
Materials Department, Jožef Stefan
Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Khaja Mohaideen Kamal
- Department
of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Blaž Likozar
- Department
of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Matjaž Spreitzer
- Advanced
Materials Department, Jožef Stefan
Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
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Wang Y, Zhang X, Zhang C, Li R, Wang Y, Fan C. Novel Bi4Ti3O12 hollow-spheres with highly-efficient CO2 photoreduction activity. INORG CHEM COMMUN 2020. [DOI: 10.1016/j.inoche.2020.107931] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Zhao X, Yang H, Li R, Cui Z, Liu X. Synthesis of heterojunction photocatalysts composed of Ag 2 S quantum dots combined with Bi 4 Ti 3 O 12 nanosheets for the degradation of dyes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:5524-5538. [PMID: 30607858 DOI: 10.1007/s11356-018-4050-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 12/19/2018] [Indexed: 06/09/2023]
Abstract
Facilitating the separation of photogenerated electron/hole pairs and widening the light-responsive region are crucial to enhance the overall photocatalytic performance of photocatalysts. To achieve this aim, here we have prepared Ag2S/Bi4Ti3O12 heterojunction composite photocatalysts by assembling Ag2S quantum dots onto the surface of Bi4Ti3O12 nanosheets. Transmission electron microscopy observation demonstrates that two types of Ag2S quantum dots separately with size of 40-70 and 7-17 nm are uniformly assembled onto the surface of large-sized Bi4Ti3O12 thin nanosheets. The as-prepared Ag2S/Bi4Ti3O12 heterojunction composites exhibit much enhanced light absorption (particularly in the visible and near-infrared region) and highly efficient separation of electrons and holes photogenerated in Bi4Ti3O12. Rhodamine B (RhB) aqueous solution was chosen as the target organic pollutant to evaluate the photocatalytic performance of the samples under simulated sunlight irradiation. It is found that the Ag2S/Bi4Ti3O12 heterojunction composites manifest significantly enhanced photocatalytic activity toward the RhB degradaton. In particular, the 15wt% Ag2S/Bi4Ti3O12 composite exhibits the highest photocatalytic activity, which is ca. 2.8 and 4.0 times higher than bare Bi4Ti3O12 and Ag2S, respectively. The enhanced photocatalytic activity of the composites can be explained as a result of the Z-scheme electron transfer from the conduction band of Bi4Ti3O12 to the valence band of Ag2S, and thus more photogenerated holes in the valence band of Bi4Ti3O12 and electrons in the conduction band of Ag2S are able to participate in the photocatalytic reactions. Active species trapping experiments were carried out, from which it is concluded that photogenerated holes and •O2- radicals play the dominant and secondary role in the photocatalysis, respectively.
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Affiliation(s)
- Xinxin Zhao
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou, 730050, China
- School of Science, Lanzhou University of Technology, Lanzhou, 730050, China
| | - Hua Yang
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou, 730050, China.
- School of Science, Lanzhou University of Technology, Lanzhou, 730050, China.
| | - Ruishan Li
- School of Science, Lanzhou University of Technology, Lanzhou, 730050, China
| | - Ziming Cui
- School of Science, Lanzhou University of Technology, Lanzhou, 730050, China
| | - Xueqin Liu
- School of Science, Chongqing University of Technology, Chongqing, 4000054, China
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Zhao X, Yang H, Cui Z, Wang X, Yi Z. Growth Process and CQDs-modified Bi₄Ti₃O 12 Square Plates with Enhanced Photocatalytic Performance. MICROMACHINES 2019; 10:E66. [PMID: 30669287 PMCID: PMC6356592 DOI: 10.3390/mi10010066] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 01/09/2019] [Accepted: 01/16/2019] [Indexed: 11/16/2022]
Abstract
Bi₄Ti₃O12 square plates were synthesized via a hydrothermal route, and their growth process was systematically investigated. Carbon quantum dots (CQDs) were prepared using glucose as the carbon source, which were then assembled on the surface of Bi₄Ti₃O12 square plates via a hydrothermal route with the aim of enhancing the photocatalytic performance. XRD (X-ray powder diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), UV-vis DRS (diffuse reflectance spectroscopy), XPS (X-ray photoelectron spectroscopy), FTIR (Fourier transform infrared spectroscopy), PL (photoluminescence) spectroscopy, EIS (electrochemical impedance spectroscopy) and photocurrent spectroscopy were used to systematically characterize the as-prepared samples. It is demonstrated that the decoration of CQDs on Bi₄Ti₃O12 plates leads to an increased visible light absorption, slightly increased bandgap, increased photocurrent density, decreased charge-transfer resistance, and decreased PL intensity. Simulated sunlight and visible light were separately used as a light source to evaluate the photocatalytic activity of the samples toward the degradation of RhB in aqueous solution. Under both simulated sunlight and visible light irradiation, CQDs@Bi₄Ti₃O12 composites with an appropriate amount of CQDs exhibit obviously enhanced photocatalytic performance. However, the decoration of excessive CQDs gives rise to a decrease in the photocatalytic activity. The enhanced photocatalytic activity of CQDs-modified Bi₄Ti₃O12 can be attributed to the following reasons: (1) The electron transfer between Bi₄Ti₃O12 and CQDs promotes an efficient separation of photogenerated electron/hole pairs in Bi₄Ti₃O12; (2) the up-conversion photoluminescence emitted from CQDs could induce the generation of additional electron/hole pairs in Bi₄Ti₃O12; and (3) the photoexcited electrons in CQDs could participate in the photocatalytic reactions.
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Affiliation(s)
- Xinxin Zhao
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Hua Yang
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Ziming Cui
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Xiangxian Wang
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Zao Yi
- Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010, China.
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Si YH, Xia Y, Shang SK, Xiong XB, Zeng XR, Zhou J, Li YY. Enhanced Visible Light Driven Photocatalytic Behavior of BiFeO₃/Reduced Graphene Oxide Composites. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E526. [PMID: 30011840 PMCID: PMC6071018 DOI: 10.3390/nano8070526] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/05/2018] [Accepted: 07/09/2018] [Indexed: 11/17/2022]
Abstract
BiFeO₃/Reduced Graphene Oxide (BFO/RGO) composites have been fabricated by a simple hydrothermal method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, and X-ray photoelectron spectroscopy (XPS) analysis reveal that graphene oxide was reduced in hydrothermal process and BFO/RGO composites were successfully synthesized. UV-visible absorption and photoluminescence properties show that the introduction of RGO can effectively reduce the recombination of photogenerated electron and hole pairs. Compared to the pristine BFO, the photocatalytic performance of BiFeO₃ Graphene Oxide (BGO) composites is enhanced for the degradation of Methylene blue (MB) solution under visible light irradiation, and the result shows that the optimal amount of Graphene Oxide (GO) in the composites is 60 mg (BGO60). The excellent photocatalytic performance is mainly ascribed to improved light absorption, increased reactive sites, and the low recombination rate of electron-hole pairs. This work can provide more insights into designing advanced photocatalysts for wastewater treatment and environmental protection.
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Affiliation(s)
- Yun-Hui Si
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Yu Xia
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Shao-Ke Shang
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Xin-Bo Xiong
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Xie-Rong Zeng
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Ji Zhou
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
| | - Ya-Yun Li
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
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