| 1. |
- Farhan, Shumail, et al.
(författare)
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Co-doped cerium oxide Fe0.25xMnxCe0.75O2-delta as a composite cathode material for IT-SOFC
- 2022
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Ingår i: Journal of Alloys and Compounds. - Amsterdam, Netherlands : Elsevier. - 0925-8388 .- 1873-4669. ; 906
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Tidskriftsartikel (refereegranskat)abstract
- In this study, Fe-Mn co-doped ceria Fe0.25Mn0.00Ce0.75O2-delta (FMDC1), Fe0.23Mn0.02Ce0.75O2-δ (FMDC2), Fe0.21Mn0.04Ce0.75O2-δ (FMDC3), and Fe0.19Mn0.06Ce0.75O2-δ (FMDC4) powders are synthesized by sol gel method and evaluated as cathode materials for intermediate temperature solid oxide fuel cell (IT-SOFC). The combination of Fe and Mn significantly enhanced the ceria catalytic activity and oxygen kinetics for redox-based reactions. The effects of the co-doping mechanism on the phase composition, optical behavior, and electrochemical performance are mainly investigated. The prepared samples are characterized by XRD, SEM, FTIR, UV-vis, and conductivity tests. X-ray diffraction analysis revealed well-developed crystallinity with a single phase cubic structure of synthesized cathode material. SEM depicted the highly porous facet for Fe0.19Mn0.06Ce0.75O2-δ (FMDC4) resulted in the large triple-phase boundaries for the reduction of ambient air. The inclusion of Mn3+ and Fe3+ ions into CeO2 network created additional oxygen vacancies (Ov) and simultaneously reduced the optical band gap energy from 2.81 eV for FMDC1 (x = 0.00) to 2.54 eV for FMDC4 (x = 0.06). Among the four samples, FMDC4 possessed the highest electrical conductivity (∼0.89 Scm-1) at 650 degrees C and corresponding low activation energy of similar to 0.301 eV, which lead to good catalytic activity with an enhanced electrochemical performance of the SOFC system. The open-circuit voltage (OCV) attained the value of ∼0.98 V, maximum power density of ∼335 mW cm-2 is obtained at 550 degrees C, which is comparable to previously reported electrodes. The results suggested that the combination of Fe and Mn into ceria can be used as an effective catalytic promoter for oxygen reduction reactions (ORR), and the composition of FMDC4 resulted in the peak conductivity, short term stability and highest power density as compared to other synthesized samples. (C) 2022 The Authors. Published by Elsevier B.V.
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| 2. |
- Sarfraz, Amina, et al.
(författare)
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Catalytic Effect of Silicon Carbide on the Composite Anode of Fuel Cells
- 2021
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Ingår i: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 4:7, s. 6436-6444
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Tidskriftsartikel (refereegranskat)abstract
- High efficiency, fuel flexibility, and sustainable energy conversion make fuel cells attractive compared to conventional energy systems. The direct ethanol fuel cells have attracted much attention because of the direct utilization of ethanol fuel. Anode materials are required to enhance the catalytic activity of the liquid fuel, which oxidize the fuel at lower operating temperature. Therefore, the catalytic effect using silicon carbide has been investigated in the LiNiO2-delta anode. The material has been characterized, and it is found that SiC shows a cubic structure and LiNiO2-delta exhibits a hexagonal structure, while the LiNiO2-delta-SiC composite exhibits a mixed cubic and hexagonal phase. Scanning electron microscopy depicts that the material is porous. The Fourier transform infrared spectroscopy analysis shows the presence of Si-O-Si, Si-C, C=O, and Si-OH bonding. The LiNiO2-delta-SiC composite (1:0.3) exhibited a maximum electrical conductivity of 1.34 S cm(-1) at 650 degrees C with an electrical band gap of 0.84 eV. The fabricated cell with the LiNiO2-delta-SiC anode exhibits a power density of 0.20 W cm(-2) at 650 degrees C with liquid ethanol fuel. The results show that there is a promising catalytic activity of SiC in the fuel cell anode.
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| 3. |
- Akbar, Muhammad, et al.
(författare)
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Effect of sintering temperature on properties of LiNiCuZn-Oxide: a potential anode for solid oxide fuel cell
- 2019
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Ingår i: Materials Research Express. - : IOP PUBLISHING LTD. - 2053-1591. ; 6:10
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Tidskriftsartikel (refereegranskat)abstract
- Crystal structure and surface morphology play vital role in the performance of Solid Oxide Fuel cells (SOFCs) anode. Sufficient electrocatalytic activity and high conductivity are the key requirements for anode to enhance the electrochemical capability. In current work, sintering temperature effects are investigated on the properties of advanced LiNiCuZn-Oxide based electrode for solid oxide fuel cells (SOFCs). The powders were prepared by simple solid-state reaction method was followed by sintering at different temperatures (700 degrees C-1200 degrees C). Moreover, various characterization techniques have been employed to investigate the sintering temperatures effects on the crystallite size, morphology, particle size, energy band gap and absorption peaks. The energy gap (Eg) was observed to increase from 2.94 eV to 3.32 eV and dc conductivity decreased from 9.084 Scm(-1) to 0.46 Scm(-1) by increasing sintering temperature from 700 degrees C to 1200 degrees C. Additionally, the best fuel cell performance of 0.90 Wcm(-2) was achieved for LiNiCuZn-Oxide sintered at 700 degrees C using H-2/air as a fuel and oxidant and it decreased to 0.17 Wcm(-2) for powders sintered at 1200 degrees C. Based on these results, we can conclude that 700 degrees C is the best optimum temperature for these chemical compositions, where all parameters of electrode are as per SOFCs requirement.
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| 4. |
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| 5. |
- Ali, Amjad, et al.
(författare)
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Effect of Manganese Catalysts on the Performance of Anodes in Direct Carbon Fuel Cells
- 2022
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Ingår i: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 5:6, s. 6878-6885
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Tidskriftsartikel (refereegranskat)abstract
- The efficiency of direct carbon fuel cells is higher than that of solid oxide fuel cells. The direct carbon fuel cell transforms chemical energy into electrical energy. In this work, the La0.4Sr0.6MnxTi1-xO3-delta (x = 0.02, 0.04, 0.06, 0.08) anode material has been synthesized by the combustion method to examine the device performance. X-ray analysis confirmed the single-perovskite cubic structure with an average crystalline size of 80 nm. An electrical conductivity of 2.1 S cm-1 and fuel cell performance of 100 mW cm-2 at 600 degrees C are measured with sub-bituminous fuel. Theoretical results describe the minor contribution of manganese (Mn) in the valence band and the major one in the conduction band, and with minimum energy, the Mn electrons may jump in the conduction band. Moreover, density functional theory confirmed that with an increase in the Mn concentration, Mn and Ti energy states appear at the Fermi level, which reveals that the conductivity of the compound has improved, agreeing with the experimental results that the Mn concentration led to the enhancement of the conductivity.
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| 6. |
- Ali, Amjad, et al.
(författare)
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Promising electrochemical study of titanate based anodes in direct carbon fuel cell using walnut and almond shells biochar fuel
- 2019
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 434
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Tidskriftsartikel (refereegranskat)abstract
- The direct carbon fuel cell (DCFC) is an efficient device that converts the carbon fuel directly into electricity with 100% theoretical efficiency contrary to practical efficiency around 60%. In this paper four perovskite anode materials La0.4Sr0.6M0.09Ti0.91O3-delta (M = Ni, Fe, Co, Zn) have been prepared using sol-gel technique to measure the performance of the device using solid fuel. These materials have shown reasonable stability and conductivity at 700 degrees C. Further structural analysis of as-prepared anode material using XRD technique reveals a single cubic perovskite structure with average crystallite size roughly 47 nm. Walnut and almond shells biochar have also been examined as a fuel in DCFC at the temperature range 400-700 degrees C. In addition, Elemental analysis of walnut and almond shells has shown high carbon content and low nitrogen and sulfur contents in the obtained biochar. Subsequently, the superior stability of as-prepared anode materials is evident by thermogravimetric analysis in pure N-2 gas atmosphere. Conversely, the LSFT anode has shown the highest electronic conductivity of 7.53Scm(-1) at 700 degrees C. The obtained power density for LSFTO3-delta composite anode mixed in sub-bituminous coal, walnut and almond shells biochar is of 68, 55, 48 mWcm(-2) respectively. A significant improvement in performance of DCFC (78 mWcm(-2)) was achieved.
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| 7. |
- Farhan, Muhammad, et al.
(författare)
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The Exploration of Cerium Metal Ions Effect on LaSrTiO3-d Ceramic Anode for Fuel Cell
- 2023
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Ingår i: Russian Journal of Physical Chemistry. - : MAIK NAUKA/INTERPERIODICA/SPRINGER. - 0036-0244 .- 1531-863X. ; 97:11, s. 2592-2602
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite based materials have become an attractive anode for fuel cell due to the significant conductivity, carbon resistivity and sulphur tolerance. Doping of Ce on B-site of the La0.4Sr0.6CexTi1-xO3-delta (x = 0.02, 0.04, 0.06, 0.08) with different dopant concentrations is prepared using sol-gel technique. The synthesized material is analyzed by numerous techniques. X-ray diffraction confirmed the cubic perovskite structure (JCPDS 01-079-0183) with average crystallite size of 35 nm. UV-Vis spectroscopy revealed the red shift in band gap (2.76 eV) compared to LaSrTiO3-delta. Scanning electron microscopy shows the homogeneity 3-delta and porosity in the prepared material. The observed particle size is in the range of 50-60 nm. The presence of the lanthanum, strontium, cerium, titanium and oxygen ions is confirmed by EDX. The Raman spectra and XRD, confirmed that cerium ions have been diffused in the lattice structure of LSTO . The 3-delta La0.4Sr0.6Ce0.08Ti0.92O3-delta anode showed the highest conductivity of 2.67 S cm(-1) with lower activation energy 3-delta of 0.20 eV as compared to other three samples. The power density of 58 mW cm-2 at 600 degrees C with 0.9 V OCV is achieved for the composition La0.4Sr0.6Ce0.08Ti0.92O3-delta using sub-bituminous fuel. The observed results show that prepared material is potential ceramic anode for direct carbon fuel cell.
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| 8. |
- Irshad, Muneeb, et al.
(författare)
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Electrochemical evaluation of mixed ionic electronic perovskite cathode LaNi1-xCoxO3-delta for IT-SOFC synthesized by high temperature decomposition
- 2021
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Ingår i: International journal of hydrogen energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-3199 .- 1879-3487. ; 46:18, s. 10448-10456
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Tidskriftsartikel (refereegranskat)abstract
- The cobalt doped perovskite cathode material LaNi1-xCoxO3-3 (x = 0.4, 0.6, 0.8) synthesized by cost effective high temperature decomposition is investigated as mixed ionic electronic conductor (MIEC) for intermediate temperature solid oxide fuel cell (IT-SOFC). LaNiO3 is known for its high electronic conductivity and to introduce more oxygen vacancies for enhancing its ionic conductivity, Ni at B site is substituted by Co. XRD analysis showed perovskite structure for all samples with no additional phases, which was also confirmed by FTIR results. Microstructure analysis revealed well connected and porous structure for LaNi1-xCoxO3-3 (x = 0.6) compared to other compositions. The elemental analysis using EDX confirmed presence of lanthanum, nickel, and cobalt within all samples. No prominent weight loss was observed during TGA analysis. The highest value of conductivity was obtained for LaNi1-xCoxO3-3 (x = 0.6) due to its porous and networked structure of sub micrometric grains. The superior performance is attained for the cell based on LaNi1-xCoxO3-3 (x = 0.6) cathode with maximum power density of 0.45 Wcm(-2) compared to other composition which can be attributed to its well connected and porous structure that caused enhanced electrochemical reaction at triple phase boundary (TPB). It was therefore deduced that LaNi1-xCoxO3-8 (x = 0.6) is promising composition to be used as MIEC cathode for IT-SOFC. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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| 9. |
- Irshad, Muneeb, et al.
(författare)
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Evaluation of BaCo0.Fe-4(0).4Zr0.2-xNixO3-delta perovskite cathode using nickel as a sintering aid for IT-SOFC
- 2021
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:24, s. 14475-14483
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Tidskriftsartikel (refereegranskat)abstract
- In this research work, BaCo0.Fe-4(0).4Zr0.2-xNixO3-delta (x = 0, 0.01, 0.02, 0.03, 0.04) perovskite cathode material for IT-SOFC is synthesized successfully using a combustion method and sintered at low temperature. The effects of nickel as a sintering aid on the properties of BaCo0.Fe-4(0).Zr-4(0).O-2(3-delta) are investigated through different characterization methods. The addition of nickel increased the densification and grain growth at a lower sintering temperature 1200 degrees C. XRD analysis confirms a single phase of BaCo0.Fe-4(0).Zr-4(0).O-2(3-delta), and an increase in crystalline size is observed. SEM micrographs show formation of dense microstructure with increased nickel concentration. TGA analysis revealed that BaCo0.Fe-4(0).4Zr0.2-xNix cathode materials are thermally stable within the SOFC temperature range, and negligible weight loss of 2.3% is observed. The bonds of hydroxyl groups and metal oxides are confirmed for all samples through FTIR analysis. The highest electrical properties are observed for BaCo0.Fe-4(0).4Zr0.2-xNix (x = 0.04) due to increased densification and electronic defects compared to other compositions. The maximum power density of 0.47 W cm(-2) is obtained for a cell having cathode material BaCo0.Fe-4(0).4Zr0.2-xNix (x = 0.02) owing to its permeable and well-connected structure compared to others.
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| 10. |
- Irshad, Muneeb, et al.
(författare)
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Evaluation of BaZr0.8X0.2 (X= Y, Gd, Sm) proton conducting electrolytes sintered at low temperature for IT-SOFC synthesized by cost effective combustion method
- 2020
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Ingår i: Journal of Alloys and Compounds. - : ELSEVIER SCIENCE SA. - 0925-8388 .- 1873-4669. ; 815
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Tidskriftsartikel (refereegranskat)abstract
- In present work, perovskite structured proton conducting electrolyte materials BaZr0.8Y0.2 (BZY), BaZr0.8Gd0.2 (BZGd) and BaZr0.8Sm0.2 (BZSm) synthesized by cost effective combustion method are investigated for intermediate temperature solid oxide fuel cell (IT-SOFC). The synthesized BZY, BZGd and BZSm materials are sintered at low temperature (1150 degrees C) and the effect of low sintering temperature on electrolyte properties are also explored. Microstructure, surface morphology, elemental composition, functional group and weight loss are studied using different characterization techniques like XRD, SEM, EDX, FTIR and TGA. XRD shows cubic perovskite structure of all synthesized materials. Secondary phase of Y2O3 is observed in BZY while BaO is observed in BZGd and BZSm due to low sintering temperature. SEM micrographs reveals dense microstructure of BZSm compared to BZY and BZGd. EDX analysis confirms the required material composition within all samples with no impurities. FTIR shows the presence of hydroxyl group and metal oxides and it is observed that BZY exhibit more structural symmetry compared to BZSm and BZGd. Highest conductivity observed (2.2 x 10(-3) S/cm) for BZY due to its structural symmetry and characteristic to prefer B-site of perovskite. Also significant power densities of 0.34 Wcm(-2), 0.24 Wcm(-2) and 0.32 Wcm(-2) for BZY, BZGd and BZSm electrolytes based cells at 650 degrees C implies that BZY, BZGd and BZSm can be used as IT-SOFC electrolytes. (C) 2019 Elsevier B.V. All rights reserved.
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