2024-03-29T13:32:42Zhttps://research-repository.st-andrews.ac.uk/oai/requestoai:research-repository.st-andrews.ac.uk:10023/73672022-04-06T11:30:15Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Boulfrad, Samir
Nechache, A.
Cassidy, Mark
Traversa, E.
Irvine, John Thomas Sirr
2015-08-31T13:40:07Z
2015-08-31T13:40:07Z
2015
Boulfrad , S , Nechache , A , Cassidy , M , Traversa , E & Irvine , J T S 2015 , Electrochemical impedance spectroscopy investigation of the anodic functionalities and processes in LSCM-CGO-Ni systems . in K Eguchi & S C Singhal (eds) , 14th International Symposium on Solid Oxide Fuel Cells, SOFC 2015 . ECS Transactions , no. 1 , vol. 68 , Electrochemical Society , pp. 2011-2018 . https://doi.org/10.1149/06801.2011ecst
9781607685395
1938-5862
PURE: 213561679
PURE UUID: 544bd97e-ffc5-4c30-8b82-a58eca6af626
Scopus: 84938801162
ORCID: /0000-0002-8394-3359/work/68280638
http://hdl.handle.net/10023/7367
https://doi.org/10.1149/06801.2011ecst
Electrochemical impedance spectroscopy was used to characterize anode compositions made of (La0.75Sr0.25)0.97Cr0.5Mn0.5O3 (LSCM) and gadolinia doped ceria (CGO) with and without additional submicron Ni, or exsoluted Ni nanoparticles. In addition, the effects of the anode gas flow rate and the working temperature were investigated. Higher content of the ionic conductor leads to a decrease of the impedance in the frequency range from 100 Hz to 10 Hz. The effect of the catalyst component was investigated while keeping the electronic conductivity unchanged in the tested materials. Enhanced catalytic activity was demonstrated to considerably decrease the impedance especially in the frequency range between 100 Hz to 1 Hz. The change in the gas flow rate affects mainly the impedance bellow 1 Hz.
eng
© The Electrochemical Society, Inc. 2015. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published here: https://dx.doi.org/10.1149/06801.2011ecst
QD Chemistry
NDAS
Electrochemical impedance spectroscopy investigation of the anodic functionalities and processes in LSCM-CGO-Ni systems
Conference item
oai:research-repository.st-andrews.ac.uk:10023/6702019-03-29T11:09:46Zcom_10023_51com_10023_18col_10023_52
Aitken, R. Alan
2009-04-16T09:31:58Z
2009-04-16T09:31:58Z
2000
Aitken, R.A. (2000). Flash Vacuum Pyrolysis of α-Acyl-o-methoxybenzylidenetriphenylphosphoranes to give 2-Substituted Benzofurans. ARKIVOC 1: 798-805
14246376
StAndrews.ResExp.Output.OutputID.5237
http://www.arkat-usa.org/get-file/18914/
http://hdl.handle.net/10023/670
The title stabilised ylides, readily prepared in one step from acid chlorides, are converted upon FVP at 850 °C into 2-substituted benzofurans. When the acyl group is aromatic it appears unchanged as the 2- substituent in the product while for aliphatic examples degradation processes may lead to 2-alkenyl products.
en
ylides
benzofurans
organic chemistry
flash vacuum pyrolysis
FVP
Flash vacuum pyrolysis of α-acyl-o-methoxybenzylidenetriphenylphosphoranes to give 2-substituted benzofurans
Journal article
oai:research-repository.st-andrews.ac.uk:10023/98382022-04-28T10:30:52Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Li, H.
Aquino, A. J. A.
Cordes, D. B.
Hase, W. L.
Krempner, C.
2016-11-17T17:30:10Z
2016-11-17T17:30:10Z
2017-02-01
Li , H , Aquino , A J A , Cordes , D B , Hase , W L & Krempner , C 2017 , ' Electronic nature of zwitterionic alkali metal methanides, silanides and germanides - a combined experimental and computational approach ' , Chemical Science , vol. 8 , no. 2 , pp. 1316-1328 . https://doi.org/10.1039/C6SC02390H
2041-6520
PURE: 247732416
PURE UUID: d68ac6ae-6558-4786-b2be-f39da150e760
RIS: urn:B6549844403E73CEBD3FD43B1C5456CB
Scopus: 85011066954
ORCID: /0000-0002-5366-9168/work/28233751
http://hdl.handle.net/10023/9838
https://doi.org/10.1039/C6SC02390H
Zwitterionic group 14 complexes of the alkali metals of formula [C(SiMe2OCH2CH2OMe)3M], (M- 1 ), [Si(SiMe2OCH2CH2OMe)3M], (M- 2 ), [Ge(SiMe2OCH2CH2OMe)3M], (M- 3 ), where M = Li, Na or K, have been prepared, structurally characterized and their electronic nature was investigated by computational methods. Zwitterions M- 2 and M- 3 were synthesized via reactions of [Si(SiMe2OCH2CH2OMe)4] ( 2 ) and [Ge(SiMe2OCH2CH2OMe)4] ( 3 ) with MOBut (M = Li, Na or K), resp., in almost quantitative yields, while M- 1 were prepared from deprotonation of [HC(SiMe2OCH2CH2OMe)3] (1) with LiBut, NaCH2Ph and KCH2Ph, resp. X-ray crystallographic studies and DFT calculations in the gas-phase, including calculations of the NPA charges confirm the zwitterionic nature of these compounds, with the alkali metal cations being rigidly locked and charge separated from the anion by the internal OCH2CH2OMe donor groups. Natural bond orbital (NBO) analysis and the second order perturbation theory analysis of the NBOs reveal significant hyperconjugative interactions in M- 1 -M- 3 , primarily between the lone pair and the antibonding Si-O orbitals, the extent of which decreases in the order M- 1 > M- 2 > M- 3 . The experimental basicities and the calculated gas-phase basicities of M- 1 -M- 3 reveal the zwitterionic alkali metal methanides M- 1 to be significantly stronger bases than the analogous silanides M- 2 and germanium M- 3 .
eng
© 2016 The Authors. Open Access article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
QD Chemistry
DAS
Electronic nature of zwitterionic alkali metal methanides, silanides and germanides - a combined experimental and computational approach
Journal article
oai:research-repository.st-andrews.ac.uk:10023/125672023-04-18T23:43:37Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Cole-Hamilton, David John
2018-01-22T14:30:05Z
2018-01-22T14:30:05Z
2017-12-07
Cole-Hamilton , D J 2017 , ' Chemistry and Brexit ' , Chemie In Unserer Zeit , vol. 51 , no. 6 , pp. 363 . https://doi.org/10.1002/ciuz.201770602
PURE: 252020577
PURE UUID: c9177fbf-8fe3-496a-92cf-14da7c246580
Scopus: 85037611545
http://hdl.handle.net/10023/12567
https://doi.org/10.1002/ciuz.201770602
eng
Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This has been made available online with permission from the journal. This is the final published version of the work, which was originally published at https://doi.org10.1002/ciuz.201770602
QD Chemistry
Chemistry and Brexit
Journal item
oai:research-repository.st-andrews.ac.uk:10023/60702022-04-14T13:30:10Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Ma, J.
Jiang, C.
Cassidy, M.
Irvine, J.T.S.
2015-02-04T09:31:23Z
2015-02-04T09:31:23Z
2014
Ma , J , Jiang , C , Cassidy , M & Irvine , J T S 2014 , Simulated biogas for nickel-based solid oxide fuel cells . in J W Fergus , Y G Guo , S D Minteer & G Zangari (eds) , 2014 Electrochemical Conference on Energy & the Environment (ECEE) . ECS Transactions , no. 1 , vol. 59 , Electrochemical Society , pp. 321-326 , 2014 Electrochemical Conference on Energy & the Environment (ECEE) , Shanghai , China , 13/03/14 . https://doi.org/10.1149/05901.0321ecst
conference
1938-6737
PURE: 212708587
PURE UUID: 087d3fff-af8e-4b4b-875b-91fe3ae86be3
Scopus: 84920568689
ORCID: /0000-0002-8394-3359/work/68280637
http://hdl.handle.net/10023/6070
https://doi.org/10.1149/05901.0321ecst
Biogas is composed of variable gases including hydrogen, nitrogen and sulphur, with methane and carbon dioxide as the main components. The common ratio of methane to carbon dioxide is 60/40 in volume and this high amount of methane causes carbon deposition when biogas is used in solid oxide fuel cells. To prevent carbon deposition, dry reforming, steam reforming or partial oxidation is the common method. In this paper, a nickel cermet solid oxide fuel cell was investigated with a simulated biogas based on 63% CH4 and 37% CO2, which was obtained by presuming 80% fuel utilisation and 25% recirculation of anode gas. Supplied with a 30 ml/min of simulated biogas, the cell generated a maximum power density of 856 mW cm-2 at 850 °C. The cell ran stably at loads of 100 mA cm-2, 300 mA cm-2and 500 mA cm-2 over a period of 16 hours at each level.
eng
© The Electrochemical Society, Inc. 2014. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published in ECS Transactions
QD Chemistry
Simulated biogas for nickel-based solid oxide fuel cells
Conference item
oai:research-repository.st-andrews.ac.uk:10023/63482022-04-14T13:30:42Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Iwawaki, T.
Habara, H.
Baton, S.
Morita, K.
Fuchs, J.
Chen, S.
Nakatsutsumi, M.
Rousseaux, C.
Filippi, F.
Nazarov, W.
Tanaka, K.A.
2015-03-26T13:01:04Z
2015-03-26T13:01:04Z
2015
Iwawaki , T , Habara , H , Baton , S , Morita , K , Fuchs , J , Chen , S , Nakatsutsumi , M , Rousseaux , C , Filippi , F , Nazarov , W & Tanaka , K A 2015 , ' Collimation of fast electrons in critical density plasma channel ' , Plasma and Fusion Research , vol. 10 . https://doi.org/10.1585/pfr.10.1304005
1880-6821
PURE: 176929467
PURE UUID: adeb3668-e992-4c21-84b8-e0ced8871345
Scopus: 84924809890
http://hdl.handle.net/10023/6348
https://doi.org/10.1585/pfr.10.1304005
http://www.jspf.or.jp/PFR/PFR_articles/pfr2015/pfr2015_10-1304005.html
Significantly collimated fast electron beam with a divergence angle 10° (FWHM) is generated through the interaction of ultra-intense laser light with a uniform critical density plasma in experiments and 2D PIC simulations. In the experiment, the uniform critical density plasma is created by ionizing an ultra-low density foam target. The spacial distribution of the fast electron is observed by Imaging Plate. 2D PIC simulation and post process analysis reveal magnetic collimation of energetic electrons along the plasma channel.
eng
Copyright 2015 The Japan Society of Plasma Science and Nuclear Fusion Research. Reproduced in accordance with publisher's copyright transfer agreement.
Ultra-intense laser
Fast electron
Plasma channeling
Electron beam
QD Chemistry
QC Physics
NDAS
Collimation of fast electrons in critical density plasma channel
Journal article
oai:research-repository.st-andrews.ac.uk:10023/51742023-04-19T00:38:44Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Gamble, Stephen Richard
Neagu, Dragos
Irvine, John Thomas Sirr
2014-08-15T15:01:01Z
2014-08-15T15:01:01Z
2013
Gamble , S R , Neagu , D & Irvine , J T S 2013 , Calculation of a standard reformed biogas composition and testing on SOFC anode powders . in ECS Transactions . 1 edn , vol. 57 , ECS Transactions , Electrochemical Society , pp. 1527-1532 , 13th International Symposium on Solid Oxide Fuel Cells , Okinawa , United Kingdom , 6/10/13 . https://doi.org/10.1149/05701.1527ecst
conference
1938-6737
PURE: 109325738
PURE UUID: 6fdaec67-8220-4a2f-85f4-ca7412196ce5
Scopus: 84905013887
ORCID: /0000-0002-8394-3359/work/68280870
http://hdl.handle.net/10023/5174
https://doi.org/10.1149/05701.1527ecst
http://ecst.ecsdl.org/content/57/1/1527.short?rss=1
EP/I037016/1
A standard reformed biogas composition, based on a 63% CH4 37% CO2 input biogas, was defined by calculation. It is designed to resemble the composition of biogas that would enter a real SOFC stack, assuming 80% fuel utilization, and 25% recirculation of the anode off-gas. It is thermodynamically impervious to coking above 720°C. This gas composition was then used to test the catalytic reforming performance of nickel powder and La0.8Ce0.1Ni0.4Ti0.6O3-δ at 900°C in the standard reformed biogas. No coking was seen on the powder samples by visual inspection after this test. The La0.8Ce0.1Ni0.4Ti0.6O3-δ is designed to exsolve Ni nanoparticles when reduced. SEM pictures of the post-test sample show some small particles that may be exsolved nanoparticles, but further investigation is needed to confirm this. Ni powder was the better reforming catalyst, but sintered extensively in the 3 h test. The La0.8Ce0.1Ni0.4Ti0.6O3-δ also showed reforming capability, and much better microstructural stability in the standard reformed biogas.
eng
© The Electrochemical Society, Inc. 2013. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published in ECS Transactions
Biogas
Catalysis
Perovskite anode
Fuel utilisation
Nanoparticles
Nickel
Coking
Stabilty
QD Chemistry
Calculation of a standard reformed biogas composition and testing on SOFC anode powders
Conference item
oai:research-repository.st-andrews.ac.uk:10023/79262023-04-18T10:04:50Zcom_10023_45com_10023_17com_10023_175com_10023_39com_10023_51com_10023_18com_10023_879com_10023_878col_10023_46col_10023_176col_10023_52col_10023_880
Constantinescu Aruxandei, Diana
Petrovic-Stojanovska, Biljana
Schiemann, Olav
Naismith, Jim
White, Malcolm F
2015-12-22T20:40:04Z
2015-12-22T20:40:04Z
2015-12-10
Constantinescu Aruxandei , D , Petrovic-Stojanovska , B , Schiemann , O , Naismith , J & White , M F 2015 , ' Taking a molecular motor for a spin : helicase mechanism studied by spin labelling and PELDOR ' , Nucleic Acids Research , vol. Advance Access . https://doi.org/10.1093/nar/gkv1373
0305-1048
PURE: 236138592
PURE UUID: 4938570e-a43a-4b48-9b61-251db030a21a
Scopus: 84966263778
ORCID: /0000-0003-1543-9342/work/47136123
WOS: 000371266000047
http://hdl.handle.net/10023/7926
https://doi.org/10.1093/nar/gkv1373
091825/Z/10/Z
BB/H017917/1
The complex molecular motions central to the functions of helicases have long attracted attention. Protein crystallography has provided transformative insights into these dynamic conformational changes, however important questions about the true nature of helicase configurations during the catalytic cycle remain. Using pulsed EPR (PELDOR or DEER) to measure interdomain distances in solution, we have examined two representative helicases: PcrA from superfamily 1 and XPD from superfamily 2. The data show that PcrA is a dynamic structure with domain movements that correlate with particular functional states, confirming and extending the information gleaned from crystal structures and other techniques. XPD in contrast is shown to be a rigid protein with almost no conformational changes resulting from nucleotide or DNA binding, which is well described by static crystal structures. Our results highlight the complimentary nature of PELDOR to crystallography and the power of its precision in understanding the conformational changes relevant to helicase function.
eng
Copyright (c) The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
QH301 Biology
NDAS
Taking a molecular motor for a spin : helicase mechanism studied by spin labelling and PELDOR
Journal article
oai:research-repository.st-andrews.ac.uk:10023/73712024-03-19T00:37:57Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Cassidy, Mark
Doherty, D.J.
Yue, Xiangling
Irvine, John Thomas Sirr
2015-08-31T14:10:02Z
2015-08-31T14:10:02Z
2015-07-17
Cassidy , M , Doherty , D J , Yue , X & Irvine , J T S 2015 , Development of tailored porous microstructures for infiltrated catalyst electrodes by aqueous tape casting methods . in K Eguchi & S C Singhal (eds) , 14th International Symposium on Solid Oxide Fuel Cells, SOFC 2015 . ECS Transactions , no. 1 , vol. 68 , Electrochemical Society , pp. 2047-2056 . https://doi.org/10.1149/06801.2047ecst
9781607685395
1938-5862
ORCID: /0000-0002-1986-9772/work/49052129
ORCID: /0000-0002-8394-3359/work/68280539
https://hdl.handle.net/10023/7371
10.1149/06801.2047ecst
EP/M014304/1
EP/J018414/1
Recent SOFC research has shown that impregnating fine catalyst structures into porous scaffolds to be an extremely promising route for electrode development. It is clear that in optimising the advantages offered by this technique there will be an obvious link between the morphology of the porous scaffold and the infiltrated catalyst. There are significant potential benefits to using aqueous systems for the manufacture of the scaffold. They include the potential for a far larger range of pore formers which may be employed to create specific pore morphologies and also reduced environmental burdens, such as exhaust handling, worker exposure and disposal. Recent and ongoing activities to develop such systems at University of St Andrews will be described. Areas of discussion will be effects of ceramic particle size, the size ratio of pore former to ceramic particle, pore former type and loading and how these interact with other tape constituents both on the behaviour during processing and on the final fired morphology. Better understanding of these complex relationships will help in designing optimised porous structures in the future.
eng
Catalysts
Ceramic materials
Electrodes
Fuel storage
Morphology
Particle size
Aqueous tape casting
Catalyst structures
Catalyst-electrodes
Complex relationships
Environmental burdens
Porous microstructure
Potential benefits
QD Chemistry
NDAS
Development of tailored porous microstructures for infiltrated catalyst electrodes by aqueous tape casting methods
Conference item
oai:research-repository.st-andrews.ac.uk:10023/52412022-04-12T14:30:25Zcom_10023_175com_10023_39com_10023_51com_10023_18com_10023_879com_10023_878col_10023_176col_10023_52col_10023_880
Perni, S.
Hackett, L.
Goss, R.J.M.
Simmons, M.J.
Overton, T.W.
2014-08-26T16:01:00Z
2014-08-26T16:01:00Z
2013-11-04
Perni , S , Hackett , L , Goss , R J M , Simmons , M J & Overton , T W 2013 , ' Optimisation of engineered Escherichia coli biofilms for enzymatic biosynthesis of L-halotryptophans ' , AMB Express , vol. 3 , pp. 1-10 . https://doi.org/10.1186/2191-0855-3-66
2191-0855
PURE: 143502194
PURE UUID: 43c28864-5e57-4027-92b4-d0a16dec383f
Scopus: 84891446993
http://hdl.handle.net/10023/5241
https://doi.org/10.1186/2191-0855-3-66
http://www.scopus.com/inward/record.url?eid=2-s2.0-84891446993&partnerID=8YFLogxK
BB/I008713/2
Engineered biofilms comprising a single recombinant species have demonstrated remarkable activity as novel biocatalysts for a range of applications. In this work, we focused on the biotransformation of 5-haloindole into 5-halotryptophan, a pharmaceutical intermediate, using Escherichia coli expressing a recombinant tryptophan synthase enzyme encoded by plasmid pSTB7. To optimise the reaction we compared two E. coli K-12 strains (MC4100 and MG1655) and their ompR234 mutants, which overproduce the adhesin curli (PHL644 and PHL628). The ompR234 mutation increased the quantity of biofilm in both MG1655 and MC4100 backgrounds. In all cases, no conversion of 5-haloindoles was observed using cells without the pSTB7 plasmid. Engineered biofilms of strains PHL628 pSTB7 and PHL644 pSTB7 generated more 5-halotryptophan than their corresponding planktonic cells. Flow cytometry revealed that the vast majority of cells were alive after 24 hour biotransformation reactions, both in planktonic and biofilm forms, suggesting that cell viability was not a major factor in the greater performance of biofilm reactions. Monitoring 5-haloindole depletion, 5-halotryptophan synthesis and the percentage conversion of the biotransformation reaction suggested that there were inherent differences between strains MG1655 and MC4100, and between planktonic and biofilm cells, in terms of tryptophan and indole metabolism and transport. The study has reinforced the need to thoroughly investigate bacterial physiology and make informed strain selections when developing biotransformation reactions.
eng
© 2013 Perni et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
E. coli
Biofilm
Biotransformation
Haloindole
Halotryptophan
QD Chemistry
Optimisation of engineered Escherichia coli biofilms for enzymatic biosynthesis of L-halotryptophans
Journal article
oai:research-repository.st-andrews.ac.uk:10023/128572024-02-15T00:47:25Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Huang, Wenxuan
Kitchaev, Daniil A.
Dacek, Stephen T.
Rong, Ziqin
Urban, Alexander
Cao, Shan
Luo, Chuan
Ceder, Gerbrand
2018-03-06T11:30:07Z
2018-03-06T11:30:07Z
2016-10-21
Huang , W , Kitchaev , D A , Dacek , S T , Rong , Z , Urban , A , Cao , S , Luo , C & Ceder , G 2016 , ' Finding and proving the exact ground state of a generalized Ising model by convex optimization and MAX-SAT ' , Physical Review B , vol. 94 , no. 13 , 134424 . https://doi.org/10.1103/PhysRevB.94.134424
2469-9950
ORCID: /0000-0002-9021-279X/work/42504550
https://hdl.handle.net/10023/12857
10.1103/PhysRevB.94.134424
Lattice models, also known as generalized Ising models or cluster expansions, are widely used in many areas of science and are routinely applied to the study of alloy thermodynamics, solid-solid phase transitions, magnetic and thermal properties of solids, fluid mechanics, and others. However, the problem of finding and proving the global ground state of a lattice model, which is essential for all of the aforementioned applications, has remained unresolved for relatively complex practical systems, with only a limited number of results for highly simplified systems known. In this paper, we present a practical and general algorithm that provides a provable periodically constrained ground state of a complex lattice model up to a given unit cell size and in many cases is able to prove global optimality over all other choices of unit cell. We transform the infinite-discrete-optimization problem into a pair of combinatorial optimization (MAX-SAT) and nonsmooth convex optimization (MAX-MIN) problems, which provide upper and lower bounds on the ground state energy, respectively. By systematically converging these bounds to each other, we may find and prove the exact ground state of realistic Hamiltonians whose exact solutions are difficult, if not impossible, to obtain via traditional methods. Considering that currently such practical Hamiltonians are solved using simulated annealing and genetic algorithms that are often unable to find the true global energy minimum and inherently cannot prove the optimality of their result, our paper opens the door to resolving longstanding uncertainties in lattice models of physical phenomena. An implementation of the algorithm is available at https://github.com/dkitch/maxsat-ising
eng
QC Physics
Electronic, Optical and Magnetic Materials
Condensed Matter Physics
DAS
Finding and proving the exact ground state of a generalized Ising model by convex optimization and MAX-SAT
Journal article
oai:research-repository.st-andrews.ac.uk:10023/73702022-04-14T13:30:13Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Irvine, John Thomas Sirr
Fuente Cuesta, Aida
Mottram, Andrew
Jiang, Cairong
Savaniu, Cristian Daniel
Jain, Sneh Lata
2015-08-31T14:10:01Z
2015-08-31T14:10:01Z
2015
Irvine , J T S , Fuente Cuesta , A , Mottram , A , Jiang , C , Savaniu , C D & Jain , S L 2015 , Utilisation of coal in direct carbon fuel cells . in S C Singhal & K Eguchi (eds) , 14th International Symposium on Solid Oxide Fuel Cells, SOFC 2015 . ECS Transactions , no. 1 , vol. 68 , Electrochemical Society , pp. 2681-2684 , ECS Conference on Electrochemical Energy Conversion & Storage with SOFC-XIV , Glasgow , United Kingdom , 26/07/15 . https://doi.org/10.1149/06801.2681ecst
conference
9781607685395
1938-6737
PURE: 212708634
PURE UUID: daf3050f-150c-4e66-a8de-d58555e80c11
Scopus: 84938792824
ORCID: /0000-0002-8394-3359/work/68280757
http://hdl.handle.net/10023/7370
https://doi.org/10.1149/06801.2681ecst
Hybrid Direct Carbon Fuel Cells merge Solid Oxide Fuel Cell (SOFC) and MCFC technologies, using a solid oxide electrolyte to separate the cathode and anode compartments, while a molten carbonate electrolyte is utilised to extend the anode/electrolyte region. Oxygen is reduced to O2- ions at the cathode and transported across the solid electrolyte membrane to the anode compartment, where carbon is oxidised to CO2. Molten carbonate could enhance the carbon oxidation in two ways as a fuel carrier or as an electrochemical mediator. The maximum energy density can be achieved by fully oxidising carbon to CO2 offering very high efficiencies. This concept has been demonstrated using a wide range of carbons and carbon-rich fuels such as coal, plastics, carbon colloids, activated carbons and charcoals. In a short stack of 3 cells delivered a maximum power output at 650°C of 5.4 W, at over 100mWcm-2. The underlying chemical processes in DCFCs are complex involving a series of catalytic and electrochemical reactions of a complex fuel. Coal and biochars are quite far from pure carbon comprising of high hydrogen content and often significant oxygen, sulphur and nitrogen contents as well as inorganic, ash components. Here we report on the pyrolysis and oxidation reactions and processes that occur in situ and in DCFC relevant conditions. Of key importance is interplay between carbon and its oxides as direct oxidation of carbon to carbon dioxide delivers the ultimate efficiency. There is a change in process above 750°C where the reverse Boudouard reaction becomes dominant and our focus is on understanding the lower temperature electrochemical processes.
eng
© The Electrochemical Society, Inc. 2015. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published here: https://dx.doi.org/10.1149/06801.2681ecst
QC Physics
NDAS
Utilisation of coal in direct carbon fuel cells
Conference item
oai:research-repository.st-andrews.ac.uk:10023/92892023-04-18T10:01:52Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Hopf, Lisa
Recker, Sebastian
Niedermaier, Matthias
Kiermaier, Stephan
Strobel, Vinzent
Maschmeyer, Dietrich
Cole-Hamilton, David
Marquardt, Wolfgang
Wasserscheid, Peter
Haumann, Marco
2016-08-11T23:33:03Z
2016-08-11T23:33:03Z
2015
Hopf , L , Recker , S , Niedermaier , M , Kiermaier , S , Strobel , V , Maschmeyer , D , Cole-Hamilton , D , Marquardt , W , Wasserscheid , P & Haumann , M 2015 , ' Comparison between phosphine and NHC-modified Pd catalysts in the telomerization of butadiene with methanol – a kinetic study combined with model-based experimental analysis ' , Chemical Engineering and Processing: Process Intensification , vol. In press . https://doi.org/10.1016/j.cep.2015.07.007
0255-2701
PURE: 209148608
PURE UUID: 0d1a8ca8-c28a-4e38-9dc9-56381b097560
RIS: urn:FDCB97B2B2680ACB9B8562E9C8F55964
Scopus: 84979222066
http://hdl.handle.net/10023/9289
https://doi.org/10.1016/j.cep.2015.07.007
246461
The telomerization of butadiene with methanol was investigated in the presence of different palladium catalysts modified either with triphenylphosphine (TPP) or 1,3-dimesityl-imidazol-2-ylidene (IMes) ligand. When pure butadiene was used as substrate, a moderate selectivity for the Pd-TPP catalyst toward the desired product 1-methoxy-2,7-octadiene (1-Mode) of around 87 % was obtained, while the IMes carbene ligand almost exclusively formed 1-Mode with 97.5 % selectivity. The selectivity remained unchanged when the pure butadiene feed was replaced by synthetic crack-C4 (sCC4), a technical feed of 45 mol% butadiene and 55 mol% inerts (butenes and butanes). The TPP-modified catalyst showed a lower reaction rate, which was attributed to the expected dilution effect caused by the inerts. Surprisingly, the IMes-modified catalyst showed a higher rate with sCC4 compared to the pure feed. By means of a model-based experimental analysis, kinetic rate equations could be derived. The kinetic modeling supports the assumption that the two catalyst systems follow different kinetic rate equations. For the Pd-TPP catalyst, the reaction kinetics were related to the Jolly mechanism. In contrast, the Jolly mechanism had to be adapted for the Pd-IMes catalyst as the impact of the base seems to differ strongly from that for the Pd-TPP catalyst. The Pd-IMes system was found to be zero order in butadiene at moderate to high butadiene concentrations and first order in base while the nucleophilicity of the base is influenced by the methanol amount resulting in a negative reaction order for methanol.
eng
Copyright © 2015 Published by Elsevier B.V. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://dx.doi.org/10.1016/j.cep.2015.07.007
Telomerization
NHC ligand
TPP ligand
Palladium
Reaction kinetics
Model-based kinetic analysis
QD Chemistry
NDAS
Comparison between phosphine and NHC-modified Pd catalysts in the telomerization of butadiene with methanol – a kinetic study combined with model-based experimental analysis
Journal article
oai:research-repository.st-andrews.ac.uk:10023/17532023-04-18T09:43:09Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Buehl, Michael
2011-03-31T15:01:09Z
2011-03-31T15:01:09Z
2011-03-21
Buehl , M 2011 , ' Dodeka(ethylene)octamine ' , Chemistry - A European Journal , vol. 17 , no. 3 , pp. 3575-3578 . https://doi.org/10.1002/chem.201002997
0947-6539
PURE: 5312417
PURE UUID: dab0c2e9-9172-4263-8eb8-9f6b8bf37006
Scopus: 79952602663
ORCID: /0000-0002-1095-7143/work/48131813
http://hdl.handle.net/10023/1753
https://doi.org/10.1002/chem.201002997
eng
This is the author's final submitted version before peer review. Published version (c) 2011 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim. The definitive version is available at www3.interscience.wiley.com
Superbases
Cubic ligand field
Density functional calculations
Proton affinities
Proton sponge
QD Chemistry
Dodeka(ethylene)octamine
Journal article
oai:research-repository.st-andrews.ac.uk:10023/167842023-04-18T23:55:30Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Zhou, Wuzong
2019-01-07T10:30:06Z
2019-01-07T10:30:06Z
2018-12-22
Zhou , W 2018 , ' Reversed crystal growth ' , Crystals , vol. 9 , no. 1 , 7 . https://doi.org/10.3390/cryst9010007
2073-4352
PURE: 257022154
PURE UUID: 42cf48c4-e906-4d19-98bd-c1683b315a6d
Scopus: 85059392069
WOS: 000458578100007
http://hdl.handle.net/10023/16784
https://doi.org/10.3390/cryst9010007
In the last decade, reversed growth route has been found in many crystal growth processes. In these systems, a single crystal does not develop from a single nucleus. The precursor molecules/ions or nanocrystallites aggregate into some large amorphous or polycrystalline particles. Multiple-nucleation on surface of the amorphous particles or surface re-crystallization of the polycrystalline particles then takes place, forming a single crystal shell with a regular morphology. Finally, the crystallization extends from the surface to the core to form single crystals. This non-classical crystal growth route often results in some special morphologies, such as core-shell structures, hollow single crystals, sandwich structures, etc. This article gives a brief review of the research in the reversed crystal growth and demonstrates that investigation of detailed mechanisms of crystal growth enables us to better understand the formation of many novel morphologies of the crystals. Some unsolved problems are also discussed.
eng
Copyright © 2018 by the author. Licensee MDPI, Basel, Switzerland. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
Crystal growth
Crystal morphology
Electron microscopy
Nucleation
Core-shell structure
Hollow crystal
QD Chemistry
Reversed crystal growth
Journal item
oai:research-repository.st-andrews.ac.uk:10023/107882023-04-18T10:09:37Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Liu, L. L.
Li, W. B.
Guo, Q. Q.
Ni, C. S.
Niu, Y.
2017-05-16T23:33:40Z
2017-05-16T23:33:40Z
2017-10
Liu , L L , Li , W B , Guo , Q Q , Ni , C S & Niu , Y 2017 , ' The corrosion behavior of a sputtered micrograin film on Fe-5Cr-5Si alloy in H 2 -CO 2 -H 2 S mixture at 700 °C ' , Corrosion Science , vol. 111 , pp. 446-453 . https://doi.org/10.1016/j.corsci.2016.05.017
0010-938X
PURE: 242630015
PURE UUID: e27b7640-62c0-45c4-904a-f0e3ea6c412d
RIS: urn:D400ABEDFE5FC6B4947832DBA5153950
Scopus: 84971667567
WOS: 000382794000041
http://hdl.handle.net/10023/10788
https://doi.org/10.1016/j.corsci.2016.05.017
The corrosion behaviors of as-cast Fe-5Cr-5Si alloy with and without sputtered Fe-5Cr-5Si film in H2-CO2-H2S mixture at 700 °C are studied. The corrosion scale forming on the as-cast alloy is non-protective and mainly composed of FeS outer layer and FeS + FeCr2O4 + Fe2SiO4 inner layer. However, a continuous Cr2O3 + SiO2 layer which possesses favorable protectiveness forms at the coating/alloy interface for the coated alloy, even though FeS layer and FeS + FeCr2O4 + Fe2SiO4 mixed layer also form. The formation mechanism of the Cr2O3 + SiO2 layer on the coated alloy is discussed thoroughly.
eng
© 2016 Published by Elsevier Ltd. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://dx.doi.org/10.1016/j.corsci.2016.05.017
A sputtered film
B SEM
B EPMA
C oxidation
C sulphidation
C selective oxidation
QD Chemistry
NDAS
The corrosion behavior of a sputtered micrograin film on Fe-5Cr-5Si alloy in H2-CO2-H2S mixture at 700 °C
Journal article
oai:research-repository.st-andrews.ac.uk:10023/73722022-04-14T13:30:23Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Myung, Jaeha
Neagu, Dragos
Tham, Mark
Irvine, John Thomas Sirr
2015-08-31T14:10:08Z
2015-08-31T14:10:08Z
2015-07-17
Myung , J , Neagu , D , Tham , M & Irvine , J T S 2015 , In situ tailored nickel nano-catalyst layer for internal reforming hydrocarbon fueled SOFCs . in K Eguchi & S C Singhal (eds) , 14th International Symposium on Solid Oxide Fuel Cells, SOFC 2015 . ECS Transactions , no. 1 , vol. 68 , Electrochemical Society , pp. 1121-1128 , ECS Conference on Electrochemical Energy Conversion & Storage with SOFC-XIV , Glasgow , United Kingdom , 26/07/15 . https://doi.org/10.1149/06801.1121ecst
conference
9781607685395
1938-5862
PURE: 213595895
PURE UUID: d80d540a-3aef-4f14-af5b-3cc0c944985f
Scopus: 84938803724
ORCID: /0000-0002-8394-3359/work/68280540
http://hdl.handle.net/10023/7372
https://doi.org/10.1149/06801.1121ecst
EP/K021036/1
Conventional Ni cermet anodes suffer from carbon deposition when they are directly used with hydrocarbon fuels due to the negative effects of pyrolysis and Boudouard reactions. In this work, the use of a non-stoichiometric perovskite, La0.8Ce0.1Ni0.4Ti0.6O3, as a reforming layer in reducing atmospheres led to the surface being highly populated with homogeneously exsolved Ni nano particles. This catalyst layer was applied to Ni-GDC anode supported and ScSZ electrolyte supported cells to prevent carbon deposition and to stabilize operation with dry methane. The catalyst layer showed both excellent attachment to the Ni-GDC anode and resistance to carbon deposition. The performance of the Ni-GDC anode-supported cells with the catalyst layer was about 1.1 W/cm2 in hydrogen fuel which is similar to that seen without the use of a catalyst layer. For the ScSZ electrolyte supported cells, the catalyst layer improved the power density and stability when in operation with dry methane.
eng
© The Electrochemical Society, Inc. 2015. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published here: https://dx.doi.org/10.1149/06801.1121ecst
QD Chemistry
NDAS
In situ tailored nickel nano-catalyst layer for internal reforming hydrocarbon fueled SOFCs
Conference item
oai:research-repository.st-andrews.ac.uk:10023/73742024-03-03T00:38:27Zcom_10023_51com_10023_18com_10023_879com_10023_878col_10023_52col_10023_880
Yue, Xiangling
Irvine, John Thomas Sirr
2015-08-31T15:10:02Z
2015-08-31T15:10:02Z
2015-07-17
Yue , X & Irvine , J T S 2015 , Understanding of CO 2 electrochemical reduction reaction process via high temperature solid oxide electrolysers . in K Eguchi & S C Singhal (eds) , 14th International Symposium on Solid Oxide Fuel Cells, SOFC 2015 . ECS Transactions , no. 1 , vol. 68 , Electrochemical Society , pp. 3535-3551 , ECS Conference on Electrochemical Energy Conversion & Storage with SOFC-XIV , Glasgow , United Kingdom , 26/07/15 . https://doi.org/10.1149/06801.3535ecst
conference
9781607685395
1938-5862
ORCID: /0000-0002-1986-9772/work/49052120
ORCID: /0000-0002-8394-3359/work/68280847
https://hdl.handle.net/10023/7374
10.1149/06801.3535ecst
EP/D07259X/1
EP/G01244X/1
EP/K015540/1
WRMA 2012/R2
The CO2 electrochemical reduction via SOEC was studied for a range of cathode materials in various operational conditions. The influences of the fuel gas composition, operating potential and temperature on cathode behavior are discussed and compared on different cathodes. The dissociative adsorption and surface diffusion of active species from CO2 reduction reaction was found to contribute dominantly to the LSCM-based cathode working in CO2-CO mixtures. Efforts were also made to obtain a high performance and durable cathode for high temperature CO2 electrolyser by employing a gradient LSCM-YSZ cathode and by adopting wet impregnation in cathode preparation. The latter was to more effective in enhancing the cathode electro-catalytic activity. A competitive cathode to Ni-YSZ cermet was fabricated by infiltrating 0.5wt% Pd and GDC into porous LSCM and YSZ layers.
eng
Catalyst activity
Cathodes
Cermets
Electrodes
Electrolytic reduction
Fuel storage
Metal drawing
Reduction
Regenerative fuel cells
Yttria stabilized zirconia
QD Chemistry
NDAS
Understanding of CO2 electrochemical reduction reaction process via high temperature solid oxide electrolysers
Conference item
oai:research-repository.st-andrews.ac.uk:10023/91532022-05-05T10:30:15Zcom_10023_51com_10023_18com_10023_126com_10023_31com_10023_879com_10023_878col_10023_52col_10023_128col_10023_880
Dugu, Sita
Pavunny, Shojan P.
Sharma, Yogesh
Scott, James F.
Katiyar, Ram S.
2016-07-16T23:31:22Z
2016-07-16T23:31:22Z
2015-07-17
Dugu , S , Pavunny , S P , Sharma , Y , Scott , J F & Katiyar , R S 2015 , ' Disorder driven structural and dielectric properties of silicon substituted strontium titanate ' , Journal of Applied Physics , vol. 118 , no. 3 , 034105 . https://doi.org/10.1063/1.4927042
0021-8979
PURE: 241963463
PURE UUID: 8a0f0f5a-165e-4d1a-9349-051f592741c3
Bibtex: urn:fcf52b28973e4c19cfe34e807a907c23
Scopus: 84937484610
http://hdl.handle.net/10023/9153
https://doi.org/10.1063/1.4927042
A systematic study on structural, microstructural, optical, dielectric, and electrical properties of phase-pure silicon-modified SrTiO3 polycrystalline electroceramics synthesized using high energy solid state reaction techniques is presented. The asymmetry and splitting in the x-ray diffractometer spectra and the observation of first order transverse optical TO2 and longitudinal optical LO4 modes in Raman spectra (nominally forbidden) revealed the distortion in the cubic lattice as a result of breaking of inversion symmetry due to doping. A bandgap Eg of 3.27 eV was determined for the sample by diffuse reflectance spectroscopy. A high dielectric constant of -400 and very low dielectric loss of -0.03 were obtained at 100 kHz near ambient conditions. The temperature dependence of the dielectric data displayed features of high temperature relaxor ferroelectric behavior as evidence of existence of polar nano-regions. The ac conductivity as a function of frequency showed features typical of universal dynamic response and obeyed a power law σac = σdc+Aωn . The temperature dependent dc conductivity followed an Arrhenius relation with activation energy of 123 meV in the 200–500 K temperature range. The linear dielectric response of Pt/SrSi0.03Ti0.97O3/Pt dielectric capacitors was well characterized. The measured leakage current was exceptionally low, 13 nA/cm2 at 8.7 kV/cm, revealing an interface blocked bulk conduction mechanism.
eng
© 2015 AIP Publishing LLC. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at: https://dx.doi.org/10.1063/1.4927042
QC Physics
NDAS
Disorder driven structural and dielectric properties of silicon substituted strontium titanate
Journal article