ORCID Profile
0000-0003-2747-1542
Current Organisation
University of Surrey
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Publisher: Informa UK Limited
Date: 2020
Publisher: IOP Publishing
Date: 21-04-2017
Publisher: Elsevier BV
Date: 12-2012
Publisher: Elsevier BV
Date: 02-2021
Publisher: Wiley
Date: 05-02-2016
Publisher: Elsevier BV
Date: 09-2023
Publisher: Springer Science and Business Media LLC
Date: 13-07-2023
Publisher: Wiley
Date: 17-03-2023
Abstract: Apatite‐type lanthanum silicate (LSO) electrolyte is one of the most promising candidates for developing intermediate‐temperature solid oxide electrolysis cells and solid oxide full cells (IT‐SOECs and SOFCs) due to its stability and low activation energy. However, the LSO electrolyte still suffers from unsatisfied ionic conductivity and low relative density. Herein, a new co‐doped method is reported to prepare highly purified polycrystalline powders of Mg−Mo co‐doped LSO (Mg/Mo‐LSO) electrolytes with high excellent densification properties and improved ionic conductivity. Introducing the Mo 6+ and Mg 2+ ions into the LSO structure can increase the number of interstitial oxide ions and improve the degree of densification at lower sintering temperatures, more importantly, expand the migration channel of oxide ions to enhance the ionic conductivity. As a result, the relative density of the fabricated Mo/Mg‐LSO electrolytes pellets could achieve more than 98 % of the theoretical density after sintering at 1500 °C for 4 h with a grain size of about 1–3 μm and the EIS results showed the ionic conductivity increased from 0.782 mS ⋅ cm −1 for the pristine LSO to 33.94 mS ⋅ cm −1 for the doped s le La 9.5 Si 5.45 Mg 0.3 Mo 0.25 O 26+δ at 800 °C. In addition, the effect of different Mo 6+ doping contents was investigated systematically, in which La 9.5 Si 5.45 Mg 0.3 Mo 0.25 O 26+δ possessed the highest ionic conductivity and relative density. The proposed Mo/Mg co‐doped method in this work is one step forward in developing apatite‐structured electrolytes offering excellent potential to address the common issues associated with the fabrication of dense, highly conductive, and thermochemically stable electrolytes for solid oxide electrolysers and fuel cells.
Publisher: MDPI AG
Date: 25-05-2023
DOI: 10.3390/EN16114318
Abstract: The rare-earth-doped zirconia-based solid electrolytes have gained significant interest in protonic ceramic fuel cell (PCFC) applications due to their high ionic conductivity. However, these solid electrolytes are susceptible to low conductivity and chemical stability at low operating temperatures, which are of interest in commercializing ceramic fuel cells. Thus, tailoring the structural properties of these electrolytes towards gaining high ionic conductivity at low/intermediate temperatures is crucial. In this study, Ce (cerium) and Nd (neodymium) co-doped barium zirconate perovskites, BaZr(0.80-x-y)CexNdyY0.10Yb0.10O3-δ (BZCNYYO) of various doping fractions (x, y: 0, 0.5, 0.10, 0.15), were synthesized (by the Pechini method) to systematically analyze their structural and conductivity properties. The X-ray diffraction patterns showed a significant lattice strain, and the stress inferences for each co-doped BZCNYYO s le were compared with Nd-cation-free reference s les, BaZrO3 and BaZr(0.80-x-y-z)CexYyYbzO3-δ (x: 0, 0.70 y: 0.20, 0.10 z: 0, 0.10). The comparative impedance investigation at low-to-intermediate temperatures (300–700 °C) showed that BaZr0.50Ce0.15Nd0.15Y0.10Yb0.10O3-δ offers the highest lattice strain and stress characteristics with an ionic conductivity (σ) of 0.381 mScm−1 at 500 °C and activation energy (Ea) of 0.47 eV. In addition, this σ value was comparable to the best reference s le BaZr0.10Ce0.70Y0.10Yb0.10O3-δ (0.404 mScm−1) at 500 °C, and it outperformed all the reference s les when the set temperature condition was ≥600 °C. The result of this study suggests that Ce- and Nd-doped BZCNYYO solid electrolytes will be a specific choice of interest for developing intermediate-temperature PCFC applications with high ionic conductivity.
Publisher: Wiley
Date: 07-03-2017
DOI: 10.1002/APP.45002
Publisher: Elsevier BV
Date: 06-2012
Publisher: Elsevier BV
Date: 07-2020
Publisher: MDPI AG
Date: 09-2021
DOI: 10.3390/EN14175440
Abstract: This review summarizes the current status, operating principles, and recent advances in high-temperature polymer electrolyte membranes (HT-PEMs), with a particular focus on the recent developments, technical challenges, and commercial prospects of the HT-PEM fuel cells. A detailed review of the most recent research activities has been covered by this work, with a major focus on the state-of-the-art concepts describing the proton conductivity and degradation mechanisms of HT-PEMs. In addition, the fuel cell performance and the lifetime of HT-PEM fuel cells as a function of operating conditions have been discussed. In addition, the review highlights the important outcomes found in the recent literature about the HT-PEM fuel cell. The main objectives of this review paper are as follows: (1) the latest development of the HT-PEMs, primarily based on polybenzimidazole membranes and (2) the latest development of the fuel cell performance and the lifetime of the HT-PEMs.
Publisher: Elsevier BV
Date: 06-2017
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.CARBPOL.2018.07.006
Abstract: This study is focused on nanocrystalline cellulose (NCC) flakes for methylene blue (MB) removal via adsorption. NCC flakes exhibit a high adsorption capacity (188.7 mg/g fixed at 0.7 g/L adsorbent dosage, 25 °C and pH 6) compared to other nanomaterials, such as carbon nanotube and other cellulosic materials, such as coffee husks. Unlike NCC powder, it was observed that NCC flakes can be easily separated from wastewater containing MB. Further adsorption studies were conducted on NCC flakes, and it was found that 0.7 g/L was the optimum adsorbent dosage, which fitted well with the Langmuir Isotherm. The mean free energy value from Dubinin-Radushkevich isotherm was less than 8 kJ/mol. ΔG
Publisher: MDPI AG
Date: 27-04-2022
DOI: 10.3390/EN15093182
Abstract: Nowadays, the ever-growing energy demands, the associated greenhouse gas emissions, and the exhaustible nature of fossil fuels are the biggest challenges of our industrial world [...]
Publisher: MDPI AG
Date: 07-02-2022
DOI: 10.3390/EN15031209
Abstract: The thermochemical water-splitting method is a promising technology for efficiently converting renewable thermal energy sources into green hydrogen. This technique is primarily based on recirculating an active material, capable of experiencing multiple reduction-oxidation (redox) steps through an integrated cycle to convert water into separate streams of hydrogen and oxygen. The thermochemical cycles are ided into two main categories according to their operating temperatures, namely low-temperature cycles ( °C) and high-temperature cycles ( °C). The copper chlorine cycle offers relatively higher efficiency and lower costs for hydrogen production among the low-temperature processes. In contrast, the zinc oxide and ferrite cycles show great potential for developing large-scale high-temperature cycles. Although, several challenges, such as energy storage capacity, durability, cost-effectiveness, etc., should be addressed before scaling up these technologies into commercial plants for hydrogen production. This review critically examines various aspects of the most promising thermochemical water-splitting cycles, with a particular focus on their capabilities to produce green hydrogen with high performance, redox pairs stability, and the technology maturity and readiness for commercial use.
Publisher: Wiley
Date: 08-11-2022
Abstract: Thermal spray coatings have the advantage of providing thick and functional coatings from a range of engineering materials. The associated coating processes provide good control of coating thickness, morphology, microstructure, pore size and porosity, and residual strain in the coatings through selection of suitable process parameters for any coating material of interest. This review consolidates scarce literature on thermally sprayed components which are critical and vital constituents (e. g., catalysts (anode/cathode), solid electrolyte, and transport layer, including corrosion‐prone parts such as bipolar plates) of the water splitting electrolysis process for hydrogen production. The research shows that there is a gap in thermally sprayed feedstock material selection strategy as well as in addressing modelling needs that can be crucial to advancing applications exploiting their catalytic and corrosion‐resistant properties to split water for hydrogen production. Due to readily scalable production enabled by thermal spray techniques, this manufacturing route bears potential to dominate the sustainable electrolyser technologies in the future. While the well‐established thermal spray coating variants may have certain limitations in the manner they are currently practiced, deployment of both conventional and novel thermal spray approaches (suspension, solution, hybrid) is clearly promising for targeted development of electrolysers.
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 12-2021
Publisher: Springer International Publishing
Date: 13-12-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1EE01532J
Publisher: Elsevier BV
Date: 08-2018
Publisher: Wiley
Date: 16-01-2012
Publisher: Elsevier BV
Date: 02-2019
Publisher: Radiological Society of North America (RSNA)
Date: 10-2020
Publisher: Elsevier BV
Date: 04-2018
Publisher: Elsevier BV
Date: 06-2011
Publisher: MDPI AG
Date: 25-06-2023
Abstract: Solid oxide fuel cells (SOFCs) are amongst the most widely used renewable alternative energy systems with near-zero carbon emission, high efficiency, and environment-friendly features. However, the high operating temperature of SOFCs is still considered a major challenge due to several issues regarding the materials’ corrosion, unwanted reactions between layers, etc. Thus, low-temperature SOFCs (LT-SOFCs) have gained significant interest during the past decades. Despite the numerous advantages of LT-SOFCs, material selection for each layer is of great importance as the common materials have not shown a desirable performance so far. In addition to the selection of the materials, fabrication techniques have a great influence on the properties of the SOFCs. As SOFCs with thinner layers showed lower polarisation resistance, especially in the electrolyte layer, different thin-film fabrication methods have been employed, and their effect on the overall performance of SOFCs has been evaluated. In this review, we aim to discuss the past and recent progress on the materials and thin-film fabrication techniques used in LT-SOFCs.
Publisher: Elsevier BV
Date: 07-2021
Publisher: Wiley
Date: 05-02-2016
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 2023
Publisher: Elsevier BV
Date: 03-2016
DOI: 10.1016/J.CARBPOL.2015.11.060
Abstract: Development of new materials for different applications especially as bio-composites has received great attention. This study concentrates on development of a biopolymer based on chitosan (CT) and halloysite nanotubes (HNT) and evaluates the copper removal intake as a potential application of this bio-composite. In this study, CT/HNT beads were prepared by ultrasonic-assisted extrusion-dripping method for the first time. Two sources of HNTs (i.e. Dragonite and Matauri Bay) were added into a chitosan solution (2wt.%) at various loading fractions (25, 50, 75wt.%). The effect of ultrasound as a mixing device was also studied by varying the litude at constant frequency of 25%, 50% and 75%. Characteristics and physical properties of the prepared CT/HNT beads were also analyzed by SEM, FTIR, TGA and BET the results show that introducing HNT to chitosan increases the adsorption capacity toward copper ions however HNT loading fraction above 50wt.% resulted in a decrease in adsorption capacity attributed to limited accessibility of the amino groups. The adsorption capacity of the CT/HNT beads prepared from Dragonite source had a larger adsorption capacity of 14.2mg/g as compared to that of Matauri Bay, 10.55mg/g. It was observed that the adsorption capacity of the beads toward copper ions decreased when the loading fraction of HNT is increased at constant ultrasound litude. The result of this study helps to understand the links between the characteristics and adsorption abilities of CT/HNT beads.
Publisher: Springer Science and Business Media LLC
Date: 23-12-2019
Publisher: Elsevier
Date: 2018
Publisher: Elsevier BV
Date: 03-2023
Publisher: Elsevier BV
Date: 06-2011
Publisher: Informa UK Limited
Date: 12-2005
Publisher: MDPI AG
Date: 26-02-2021
DOI: 10.3390/EN14051280
Abstract: Solid oxide fuel cells (SOFCs) have been considered as promising candidates to tackle the need for sustainable and efficient energy conversion devices. However, the current operating temperature of SOFCs poses critical challenges relating to the costs of fabrication and materials selection. To overcome these issues, many attempts have been made by the SOFC research and manufacturing communities for lowering the operating temperature to intermediate ranges (600–800 °C) and even lower temperatures (below 600 °C). Despite the interesting success and technical advantages obtained with the low-temperature SOFC, on the other hand, the cell operation at low temperature could noticeably increase the electrolyte ohmic loss and the polarization losses of the electrode that cause a decrease in the overall cell performance and energy conversion efficiency. In addition, the electrolyte ionic conductivity exponentially decreases with a decrease in operating temperature based on the Arrhenius conduction equation for semiconductors. To address these challenges, a variety of materials and fabrication methods have been developed in the past few years which are the subject of this critical review. Therefore, this paper focuses on the recent advances in the development of new low-temperature SOFCs materials, especially low-temperature electrolytes and electrodes with improved electrochemical properties, as well as summarizing the matching current collectors and sealants for the low-temperature region. Different strategies for improving the cell efficiency, the impact of operating variables on the performance of SOFCs, and the available choice of stack designs, as well as the costing factors, operational limits, and performance prospects, have been briefly summarized in this work.
Publisher: MDPI AG
Date: 15-03-2019
DOI: 10.3390/EN12061007
Abstract: Biogas is a renewable, as well as abundant, fuel source which can be utilised in the production of heat and electricity as an alternative to fossil fuels. Biogas can additionally be upgraded via the dry reforming reactions into high value syngas. Nickel-based catalysts are well studied for this purpose but have shown little resilience to deactivation caused by carbon deposition. The use of bi-metallic formulations, as well as the introduction of promoters, are hence required to improve catalytic performance. In this study, the effect of varying compositions of model biogas (CH4/CO2 mixtures) on a promising multicomponent Ni-Sn/CeO2-Al2O3 catalyst was investigated. For intermediate temperatures (650 °C), the catalyst displayed good levels of conversions in a surrogate sewage biogas (CH4/CO2 molar ratio of 1.5). Little deactivation was observed over a 20 h stability run, and greater coke resistance was achieved, related to a reference catalyst. Hence, this research confirms that biogas can suitably be used to generate H2-rich syngas at intermediate temperatures provided a suitable catalyst is employed in the reaction.
Publisher: MDPI AG
Date: 08-04-2023
DOI: 10.3390/EN16083327
Abstract: Hydrogen is known to be the carbon-neutral alternative energy carrier with the highest energy density. Currently, more than 95% of hydrogen production technologies rely on fossil fuels, resulting in greenhouse gas emissions. Water electrolysis is one of the most widely used technologies for hydrogen generation. Nuclear power, a renewable energy source, can provide the heat needed for the process of steam electrolysis for clean hydrogen production. This review paper analyses the recent progress in hydrogen generation via high-temperature steam electrolysis through solid oxide electrolysis cells using nuclear thermal energy. Protons and oxygen-ions conducting solid oxide electrolysis processes are discussed in this paper. The scope of this review report covers a broad range, including the recent advances in material development for each component (i.e., hydrogen electrode, oxygen electrode, electrolyte, interconnect, and sealant), degradation mechanisms, and countermeasures to mitigate them.
Publisher: IOP Publishing
Date: 20-08-2018
Publisher: Elsevier BV
Date: 2019
Publisher: Wiley
Date: 24-08-2016
DOI: 10.1111/JACE.14411
Publisher: Elsevier BV
Date: 10-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3ME00011G
Abstract: A lithium–bismuth–copper co-doped GDC composite (Ce 0.712 Gd 0.178 Li 0.05 Bi 0.05 Cu 0.01 O 1.801 ) capable of sintering at ∼750 °C with an electrical conductivity of 29.6 mS cm −1 was developed for the first time for metal-supported solid oxide electrolysers.
Publisher: MDPI AG
Date: 13-04-2022
DOI: 10.3390/EN15082826
Abstract: Zirconia-based composites with high thermochemical stability and electrochemical activity are the most promising solid electrolytes for manufacturing solid oxide fuel cells (SOFCs). In the present work, nanocrystalline composite powders of gadolinium-doped zirconia (GDZ: Gd2xZr2(1−x)O4−x) with various doping fractions (0.01 ≤ x ≤ 0.16) were synthesized by the Pechini method and applied for the fabrication of several electrolyte pellets to evaluate their physicochemical properties, sinterability, and conductivity. The X-ray diffraction (XRD) patterns and the thermogravimetry/differential thermal analysis (TGA/DTA) of the synthesized powders confirmed the successful formation of nanocrystalline GDZ in the tetragonal phase with complete substitution of gadolinium phase into the zirconia (ZrO2) lattice. The synthesized gadolinium zirconate powders were then shaped into pellet forms using the tape casting method, followed by sintering at 1300 °C (for 2.5 h). The microstructural analysis of the electrolyte pellets showed suitable grain boundary welding at the surface with an acceptable grain growth at the bulk of the T-phase GDZ s les. The impedance measurements indicated that the T-phase GDZ-8 could provide a comparably higher ionic conductivity (with 7.23 × 10−2 S/cm in the air at 800 °C) than the other dopant fractions. The results of this work can help better understand the characteristics and electrochemical performance of the T-phase gadolinium zirconate as a potential electrolyte for the fabrication of SOFCs.
Location: Iran (Islamic Republic of)
Location: Iran (Islamic Republic of)
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2021
End Date: 2022
Funder: Royal Academy of Engineering
View Funded ActivityStart Date: 2020
End Date: 2021
Funder: Royal Society
View Funded ActivityStart Date: 2017
End Date: 2018
Funder: University of Surrey
View Funded ActivityStart Date: 2019
End Date: 2020
Funder: University of Surrey
View Funded Activity