Development and testing of impregnated La0.20Sr0.25Ca0.45TiO3 anode microstructures for solid oxide fuel cells

Funding: EPSRC project EP/M014304/1 “Tailoring of Microstructural Evolution in Impregnated SOFC Electrodes”, the University of St Andrews and HEXIS AG.The A-site deficient perovskite: La0.20Sr0.25Ca0.45TiO3 (LSCTA-) is a mixed ionic and electronic conductor (MIEC) which shows promising performance as a Solid Oxide Fuel Cell (SOFC) anode ‘backbone’ material, when impregnated with metallic and oxide-ion conducting electrocatalysts. Here, we present data on the complete ceramic processing and optimisation of the LSCTA- ‘backbone’ microstructure, in order to improve current distribution throughout the anode. Through control of ink rheology, screen printing parameters and sintering protocol an advantageous LSCTA- microstructural architecture was developed, exhibiting an ‘effective’ conductivity of 21 S cm-1. Incorporation of this LSCTA- anode microstructure into SOFC and impregnation with Ce0.80Gd0.20O1.9 and either Ni, Ru, Rh, Pt or Pd resulted in promising initial performances during fuel cell testing in a fuel stream of 97% H2:3% H2O. Area Specific Resistances of 0.41 Ω cm2 and 0.39 Ω cm2 were achieved with anodes containing Rh/CGO and Pd/CGO, respectively.Postprin

Development and testing of impregnated La0.20Sr0.25Ca0.45TiO3 anode microstructures for solid oxide fuel cells

Funding: EPSRC project EP/M014304/1 “Tailoring of Microstructural Evolution in Impregnated SOFC Electrodes”, the University of St Andrews and HEXIS AG.The A-site deficient perovskite: La0.20Sr0.25Ca0.45TiO3 (LSCTA-) is a mixed ionic and electronic conductor (MIEC) which shows promising performance as a Solid Oxide Fuel Cell (SOFC) anode ‘backbone’ material, when impregnated with metallic and oxide-ion conducting electrocatalysts. Here, we present data on the complete ceramic processing and optimisation of the LSCTA- ‘backbone’ microstructure, in order to improve current distribution throughout the anode. Through control of ink rheology, screen printing parameters and sintering protocol an advantageous LSCTA- microstructural architecture was developed, exhibiting an ‘effective’ conductivity of 21 S cm-1. Incorporation of this LSCTA- anode microstructure into SOFC and impregnation with Ce0.80Gd0.20O1.9 and either Ni, Ru, Rh, Pt or Pd resulted in promising initial performances during fuel cell testing in a fuel stream of 97% H2:3% H2O. Area Specific Resistances of 0.41 Ω cm2 and 0.39 Ω cm2 were achieved with anodes containing Rh/CGO and Pd/CGO, respectively.Postprin

Durability of La0.20Sr0.25Ca0.45TiO3-based SOFC anodes : identifying sources of degradation in Ni and Pt/ceria co-impregnated fuel electrode microstructures

Funding from the University of St Andrews and HEXIS AG is acknowledged, in addition to the EPSRC Grants: EP/M014304/1 “Tailoring of Microstructural Evolution in Impregnated SOFC Electrodes” and EP/L017008/1 “Capital for Great Technologies”.Solid oxide fuel cells (SOFC) comprising LSM-YSZ/LSM composite cathodes, 6ScSZ electrolytes and La0.20Sr0.25Ca0.45TiO3 (LSCTA−) anode ‘backbone’ microstructures were prepared using thick-film ceramic processing techniques. Activation and decoration of the LSCTA− anode ‘backbone’ with electrocatalytic coatings of cerium-based oxides and metallic Ni or Pt particles was achieved using the technique of catalyst co-impregnation. SOFC containing Ni/CGO, Ni/CeO2 and Pt/CGO impregnated LSCTA anodes were tested up to ∼1000 hours by the Swiss SOFC manufacturer: HEXIS, under realistic operating conditions, including 15 redox, thermo and thermoredox cycles. The voltage degradation rates observed over the entire test period for the SOFC containing the Ni/CGO, Ni/CeO2 and Pt/CGO impregnated LSCTA− anodes were 14.9%, 7.7% and 13.4%, respectively. Post-mortem microscopic analyses indicated that CeO2 formed ubiquitous coatings upon the LSCTA− anode microstructure, allowing retention of a high population density of metallic (Ni) particles, whilst CGO formed ‘islands’ upon the microstructure and some agglomerates within the pores, leading to more facile agglomeration of metallic (Ni and Pt) nanoparticles. Correlation of the post-mortem microscopy with AC impedance analysis revealed that the agglomeration of metallic catalyst resulted in an increase in the high-frequency anode polarisation resistance, whilst agglomeration of the ceria-based component directly resulted in the development of a low-frequency process that may be attributed to combined contributions from gas conversion and chemical capacitance.PostprintPostprintPeer reviewe

Development and full system testing of novel co-impregnated La0.20Sr0.25Ca0.45TiO3 anodes for commercial combined heat and power units

Funding: Engineering and Physical Sciences Research Council. Grant Numbers: EP/J016454/1, EP/P024807/1; HEXIS AG.Over the past decade, the University of St Andrews and HEXIS AG have engaged in a highly successful collaborative project aiming to develop and upscale La0.20Sr0.25Ca0.45TiO3 (LSCTA-) anode “backbone” microstructures, impregnated with Ce0.80Gd0.20O1.90 (CG20) and metallic electrocatalysts, providing direct benefits in terms of performance and stability over the current state-of-the-art (SoA) Ni-based cermet solid oxide fuel cell (SOFC) anodes. Here, we present a brief overview of previous work performed in this research project, including short-term, durability, and poison testing of small-scale (1 cm2 area) SOFCs and upscaling to full-sized HEXIS SOFCs (100 cm2 area) in short stacks. Subsequently, recent results from short stack testing of SOFCs containing LSCTA- anodes with a variety of metallic catalyst components (Fe, Mn, Ni, Pd, Pt, Rh, or Ru) will be presented, indicating that only SOFCs containing the Rh catalyst provide comparable degradation rates to the SoA Ni/cerium gadolinium oxide anode, as well as tolerance to harsh overload conditions (which is not exhibited by SoA anodes). Finally, results from full system testing (60 cells within a 1.5 kW electrical power output HEXIS Leonardo FC40A micro-combined heat and power unit), will be outlined, demonstrating the robust and durable nature of these novel oxide electrodes, in addition to their potential for commercialization.Publisher PDFPeer reviewe

Microstructure dependence of performance degradation for intermediate temperature solid oxide fuel cells based on the metallic catalyst infiltrated La- and Ca-doped SrTiO3 anode support

The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement No. 256730 and Energy Technology Partnership (ETP). C. Ni also would like to thank the support from the Natural Science Foundation of China (NSFC, 51702264) Fundamental Research Funds for the Central Universities (XDJK2017B033) and Research Funding of Southwest University (SWU117019).Anode-supported solid oxide fuel cells with the configuration of the La0.2Sr0.25Ca0.45TiO3 (LSCTA-) anode, YSZ electrolyte and La0.8Sr0.2Co0.2Fe0.8O3 (LSCF)-YSZ cathode were fabricated using tape casting and co-sintering techniques followed by pre-reduction and impregnation. In order to improve the performance, the active anodes were prepared via the wet impregnation of metallic catalysts (Ni or Ni-Fe solution). The impregnation of 3 wt% nickel significantly improved the fuel cell performance from 43 mW cm-2 for the bare LSCTA- anode to 112 mW cm-2 for the Ni-LSCTA- anode at 700 °C in humidified hydrogen containing 3 vol% H2O. More interestingly, the substitution of 25 wt% Fe to Ni further enhances the power density by a factor of 1.5, compared to the Ni-impregnated cell. The cell infiltrated with Ni-Fe solid solution shows a slower degradation than the other two cells after the first 20 h period. High-resolution back-scattered electron (BSE) and transmission electron microscopy (TEM) images performed on the cross section of the impregnated anodes with time after ion beam preparation show that the sintering of the catalyst particles on the scaffold surface and the interaction between backbone and catalyst are the predominant contributions for the degradation of cell performance.PostprintPeer reviewe

Water first aid is beneficial in humans post-burn: evidence from a bi-national cohort study

Introduction: Reported first aid application, frequency and practices around the world vary greatly. Based primarily on animal and observational studies, first aid after a burn injury is considered to be integral in reducing scar and infection, and the need for surgery. The current recommendation for optimum first aid after burn is water cooling for 20 minutes within three hours. However, compliance with this guideline is reported as poor to moderate at best and evidence exists to suggest that overcooling can be detrimental. This prospective cohort study of a binational burn patient registry examined data collected between 2009 and 2012. The aim of the study was to quantify the magnitude of effects of water cooling first aid after burn on indicators of burn severity in a large human cohort. Method: The data for the analysis was provided by the Burn Registry of Australia and New Zealand (BRANZ). The application of first aid cooling prior to admission to a dedicated burn service, was analysed for its influence on four outcomes related to injury severity. The patient related outcomes were whether graft surgery occurred, and death while the health system (cost) outcomes included total hospital length of stay and admission to ICU. Robust regression analysis using bootstrapped estimation adjusted using a propensity score was used to control for confounding and to estimate the strength of association with first aid. Dose-response relationships were examined to determine associations with duration of first aid. The influence of covariates on the impact of first aid was assessed. Results: Cooling was provided before Burn Centre admission for 68% of patients, with at least twenty minutes duration for 46%. The results indicated a reduction in burn injury severity associated with first aid. Patients probability for graft surgery fell by 0.070 from 0.537 (13% reduction) (p = 0.014). The probability for ICU admission fell by 0.084 from 0.175 (48% reduction) (p (p = 0.001). All outcomes except death showed a dose-response relationship with the duration of first aid. The size of burn and age interacted with many of the relationships between first aid and outcome and these are described and discussed. Discussion & Conclusion: This study suggests that there are significant patient and health system benefits from cooling water first aid, particularly if applied for up to 20 minutes. The results of this study estimate the effect size of post-burn first aid and confirm that efforts to promote first aid knowledge are not only warranted, but provide potential cost savings

Distribution of Brevetoxin (PbTx-3) in Mouse Plasma: Association with High-Density Lipoproteins

We investigated the brevetoxin congener PbTx-3 to determine its distribution among carrier proteins, including albumin and blood lipoproteins. Using a radiolabeled brevetoxin tracer (PbTx-3), we found that 39% of the radiolabel remained associated with components in mouse plasma after > 15 kDa cutoff dialysis. Of this portion, only 6.8% was bound to serum albumin. We also examined the binding of brevetoxin to various lipoprotein fractions. Plasma, either spiked with PbTx-3 or from mice treated for 30 min with PbTx-3, was fractionated into different-sized lipoproteins by iodixanol gradient ultracentrifugation. Each fraction was then characterized and quantified by agarose gel electrophoresis and brevetoxin radioimmunoassay, respectively. In both the in vitro and in vivo experiments, the majority of brevetoxin immunoreactivity was restricted to only those gradient fractions that contained high-density lipoproteins (HDLs). Independent confirmation of brevetoxin binding to HDLs was provided by high molecular weight (100 kDa cutoff) dialysis of [(3)H]PbTx-3 from lipoprotein fractions as well as a scintillation proximity assay using [(3)H]PbTx-3 and purified human HDLs. This information on the association of brevetoxins with HDLs provides a new foundation for understanding the process by which the toxin is delivered to and removed from tissues and may permit more effective therapeutic measures to treat intoxication from brevetoxins and the related ciguatoxins

Epidemiological, clinical and genetic aspects of adult onset isolated focal dystonia in Ireland

Background: Adult onset idiopathic isolated focal dystonia presents with a number of phenotypes. Reported prevalence rates vary considerably; well-characterized cohorts are important to our understanding of this disorder. Aim: To perform a nationwide epidemiological study of adult onset idiopathic isolated focal dystonia in the Republic of Ireland. Methods: Patients with adult onset idiopathic isolated focal dystonia were recruited from multiple sources. Diagnosis was based on assessment by a neurologist with an expertise in movement disorders. When consent was obtained, a number of clinical features including family history were assessed. Results: On the prevalence date there were 592 individuals in Ireland with adult onset idiopathic isolated focal dystonia, a point prevalence of 17.8 per 100 000 (95% confidence interval 16.4-19.2). Phenotype numbers were cervical dystonia 410 (69.2%), blepharospasm 102 (17.2%), focal hand dystonia 39 (6.6%), spasmodic dysphonia 18 (3.0%), musician\u27s dystonia 17 (2.9%) and oromandibular dystonia six (1.0%). Sixty-two (16.5%) of 375 consenting index cases had a relative with clinically confirmed adult onset idiopathic isolated focal dystonia (18 multiplex and 24 duplex families). Marked variations in the proportions of patients with tremor, segmental spread, sensory tricks, pain and psychiatric symptoms by phenotype were documented. Conclusions: The prevalence of adult onset idiopathic isolated focal dystonia in Ireland is higher than that recorded in many similar service-based epidemiological studies but is still likely to be an underestimate. The low proportion of individuals with blepharospasm may reflect reduced environmental exposure to sunlight in Ireland. This study will serve as a resource for international comparative studies of environmental and genetic factors in the pathogenesis of the disorder

Epistatic and Combinatorial Effects of Pigmentary Gene Mutations in the Domestic Pigeon

SummaryUnderstanding the molecular basis of phenotypic diversity is a critical challenge in biology, yet we know little about the mechanistic effects of different mutations and epistatic relationships among loci that contribute to complex traits. Pigmentation genetics offers a powerful model for identifying mutations underlying diversity and for determining how additional complexity emerges from interactions among loci. Centuries of artificial selection in domestic rock pigeons (Columba livia) have cultivated tremendous variation in plumage pigmentation through the combined effects of dozens of loci. The dominance and epistatic hierarchies of key loci governing this diversity are known through classical genetic studies [1–6], but their molecular identities and the mechanisms of their genetic interactions remain unknown. Here we identify protein-coding and cis-regulatory mutations in Tyrp1, Sox10, and Slc45a2 that underlie classical color phenotypes of pigeons and present a mechanistic explanation of their dominance and epistatic relationships. We also find unanticipated allelic heterogeneity at Tyrp1 and Sox10, indicating that color variants evolved repeatedly though mutations in the same genes. These results demonstrate how a spectrum of coding and regulatory mutations in a small number of genes can interact to generate substantial phenotypic diversity in a classic Darwinian model of evolution [7]

Production and stability of low amount fraction of formaldehyde in hydrogen gas standards

Formaldehyde is an intermediate of the steam methane reforming process for hydrogen production. According to International Standard ISO 14687-2 the amount fraction level of formaldehyde present in hydrogen supplied to fuel cell electric vehicles (FCEV) must not exceed 10 nmol mol−1. The development of formaldehyde standards in hydrogen is crucial to validate the analytical results and ensure measurement reliability for the FCEV industry. NPL demonstrated that these standards can be gravimetrically prepared and validated at 10 μmol mol−1 with a shelf-life of 8 weeks (stability uncertainty <10%; k = 1), but that formaldehyde degrades into methanol and dimethoxymethane, as measured by FTIR, GC-MS and SIFT-MS. The degradation kinetics is more rapid than predicted by thermodynamics, this may be due to the internal gas cylinder surface acting as a catalyst. The identification of by-products (methanol and dimethoxymethane) requires further investigation to establish any potential undesirable impacts to the FCEV