Designing transition metal chalcogenides electrocatalyst surfaces for high-efficiency water oxidation

”The rising demand for energy security and reducing fossil fuel dependence has prompted researchers to search for a clean, sustainable, and efficient energy generation system with low environmental impact. Water electrolysis has been identified as one of the most important processes satisfying the above needs to generate hydrogen as a clean fuel. Two half-cell reactions of oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction (HER) at the cathode comprise the main process of water electrolysis. However, the oxygen evolution reaction is the most crucial step for efficient water splitting. Traditionally, metal oxides have been utilized as catalysts to enhance OER. Recent developments however have shown that transition metal chalcogenides exhibit better OER electrocatalytic activity surpassing state-of-the-art precious oxides. In this research, the design principle of these electrocatalysts was explored further and the highly efficient OER catalytic activity of tellurides with various transition metals including Ni and Co was demonstrated. Interestingly it was observed that telluride-based electrocatalysts exhibited some of the lowest overpotentials reported to date along with high current density, surpassing those reported with analogous oxides and selenides. This research thus validated the primary hypothesis that decreasing anion electronegativity is instrumental in improving electrocatalytic activity, by tuning electrochemical response around the active transition metal site. This project also focused on understanding the active surface composition of chalcogenide electrocatalysts by measuring the catalytic activity of tailor-made surfaces and comparing it with constructed surface models. The effect of nanostructuring on the electrocatalytic performance was also investigated”--Abstract, page iv

Prevalence of complex post-traumatic stress disorder in refugees and asylum seekers: systematic review

BACKGROUND: Refugees and asylum seekers often report having experienced numerous complex traumas. It is important to understand the prevalence of complex post-traumatic stress disorder (CPTSD), which can follow complex traumas. AIMS: This systematic review aims to summarise the available literature reporting the prevalence in refugees and asylum seekers of three operationalised definitions of CPTSD: the ICD-11 diagnostic criteria, the ICD-10 criteria (for enduring personality change after catastrophic experience) and the DSM-IV criteria (for disorders of extreme stress not otherwise specified). METHOD: Six electronic databases were searched for studies reporting the prevalence of CPTSD in adult refugee and/or asylum-seeking samples. Owing to heterogeneity between the studies, a narrative synthesis approach was used to summarise studies. Methodological quality was assessed using the Joanna Briggs Critical Appraisal Checklist for Prevalence Studies. This systematic review has been registered with PROSPERO (registration number CRD42020188422, https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=188422). RESULTS: Systematic searches identified 15 eligible studies, with 10 examining treatment-seeking samples and five using population samples. CPTSD prevalence in treatment-seeking samples was between 16 and 38%. Prevalence in population samples ranged from 2.2 to 9.3% in four studies, with the fifth reporting a much higher estimate (50.9%). CONCLUSIONS: This review highlights both the high prevalence of CPTSD in treatment samples and the lack of research aiming to establish prevalence of CPTSD in refugee and asylum-seeking populations. Understanding the prevalence of these disabling disorders has implications for policy and healthcare services for the appropriate promotion, planning and provision of suitable treatment and interventions for this highly traumatised population

Ultrasensitive and Highly Selective Ni₃Te₂ as a Nonenzymatic Glucose Sensor at Extremely Low Working Potential

Developing Nonenzymatic glucose biosensors has recently been at the center of attention owing to their potential application in implantable and continuous glucose monitoring systems. In this article, nickel telluride nanostructure with the generic formula of Ni3Te2 has been reported as a highly efficient electrocatalyst for glucose oxidation, functional at a low operating potential. Ni3Te2 nanostructures were prepared by two synthesis methods, direct electrodeposition on the electrode and hydrothermal method. The electrodeposited Ni3Te2 exhibited a wide linear range of response corresponding to glucose oxidation exhibiting a high sensitivity of 41.615 mA cm-2 mM-1 and a low limit of detection (LOD) of 0.43 µM. The hydrothermally synthesized Ni3Te2, on the other hand, also exhibits an ultrahigh sensitivity of 35.213 mA cm-2 mM-1 and an LOD of 0.38 µM. The observation of high efficiency for glucose oxidation for both Ni3Te2 electrodes irrespective of the synthesis method further confirms the enhanced intrinsic property of the material toward glucose oxidation. In addition to high sensitivity and low LOD, Ni3Te2 electrocatalyst also has good selectivity and long-term stability in a 0.1 M KOH solution. Since it is operative at a low applied potential of 0.35 V vs Ag|AgCl, interference from other electrochemically active species is reduced, thus increasing the accuracy of this sensor

Colombo District.

Objective To assess the quality of care in government family planning clinic services in Colombo District

Nickel telluride as a bifunctional electrocatalyst for efficient water splitting in alkaline medium

Designing efficient electrocatalysts has been one of the primary goals for water electrolysis, which is one of the most promising routes towards sustainable energy generation from renewable sources. In this article, we have tried to expand the family of transition metal chalcogenide based highly efficient OER electrocatalysts by investigating nickel telluride, Ni3Te2 as a catalyst for the first time. Interestingly Ni3Te2 electrodeposited on a GC electrode showed very low onset potential and overpotential at 10 mA cm-2 (180 mV), which is the lowest in the series of chalcogenides with similar stoichiometry, Ni3E2 (E = S, Se, Te) as well as Ni-oxides. This observation falls in line with the hypothesis that increasing the covalency around the transition metal center enhances catalytic activity. Such a hypothesis has been previously validated in oxide-based electrocatalysts by creating anion vacancies. However, this is the first instance where this hypothesis has been convincingly validated in the chalcogenide series. The operational stability of the Ni3Te2 electrocatalyst surface during the OER for an extended period of time in alkaline medium was confirmed through surface-sensitive analytical techniques such as XPS, as well as electrochemical methods which showed that the telluride surface did not undergo any corrosion, degradation, or compositional change. More importantly we have compared the catalyst activation step (Ni2+ → Ni3+ oxidation) in the chalcogenide series, through electrochemical cyclic voltammetry studies, and have shown that catalyst activation occurs at lower applied potential as the electronegativity of the anion decreases. From DFT calculations we have also shown that the hydroxyl attachment energy is more favorable on the Ni3Te2 surface compared to the Ni-oxide, confirming the enhanced catalytic activity of the telluride. Ni3Te2 also exhibited efficient HER catalytic activity in alkaline medium making it a very effective bifunctional catalyst for full water splitting with a cell voltage of 1.66 V at 10 mA cm-2. It should be noted here that this is the first report of OER and HER activity in the family of Ni-tellurides

Cobalt Telluride: A Highly Efficient Trifunctional Electrocatalyst for Water Splitting and Oxygen Reduction

Cobalt telluride has been identified as an efficient multifunctional electrocatalyst for oxygen and hydrogen evolution reactions and oxygen reduction reaction in alkaline medium. Both hydrothermally synthesized and electrodeposited, CoTe and CoTe2 show efficient electrocatalytic activities. CoTe shows better efficiency for OER with a low Tafel slope (43.8 mV dec-1) and lower overpotential (200 mV) at 10 mA cm-2 compared to CoTe2. DFT studies have also been performed which revealed that CoTe showed higher adsorption energy for intermediate-OH adsorption on the catalyst surface, which corresponds to the catalyst activation step. Comparison of the-OH adsorption energies (Eads) on different catalyst surfaces with the observed overpotential also revealed that this Eads can be used as an appropriate descriptor for benchmarking catalytic efficiencies. Both CoTe and CoTe2 exhibited improved OER catalytic efficiency compared to Co3O4, confirming the primary hypothesis that decreasing anion electronegativity enhances catalytic efficiency by virtue of increasing lattice covalency around the catalytically active site. The difference in OER catalytic activity between CoTe and CoTe2 could be explained from fundamental materials chemistry concepts by comparing their lattice structures which showed different packing density of catalytically active Co sites as well as varying unsaturation of Co-Terminated surfaces. Band structure calculations also corroborated such differences and could potentially explain the difference in activity due to observed differences in electron density distribution around the catalytically active Co site. The cobalt telluride compositions also showed moderate HER and ORR activity in alkaline medium, making them trifunctional catalysts which can be used in practical devices. Both CoTe and CoTe2 showed extensive functional and compositional stability for OER, HER, and ORR, under continuous operation in alkaline medium for over 24 h with less than 5% degradation of current density. The excellent compositional stability of each catalyst was revealed by detailed electrochemical measurements and surface and bulk analytical characterizations, which confirmed that there was no catalyst leaching even with long-Term operation and no other impurity enrichment in the electrolyte

Understanding the Structural Evolution of a Nickel Chalcogenide Electrocatalyst Surface for Water Oxidation

Recently, nickel-selenide- and -telluride-based electrocatalysts have shown promising results toward water electrolysis, exhibiting very low overpotential. However, a major challenge for these chalcogenide-based electrocatalysts has been correct identification of catalytically active species on the surface, with common concern being that the surface is totally being converted to nickel oxide, which becomes the true catalytically active species. In this Article, we have attempted to understand evolution of the active surface composition for nickel-selenide- and -telluride-based electrocatalysts by intentionally creating nickel-oxide-coated Ni3Se2 and Ni3Te2 surfaces and comparing their electrocatalytic activity with pristine and aged (subjected to a KOH electrolyte for an extended period) Ni3Se2 and Ni3Te2 surfaces, respectively. From such a comparison, it could be confirmed that catalytically active Ni3Se2 and Ni3Te2 surfaces were in fact stable in alkaline medium and were not coated with nickel oxide even after prolonged exposure to KOH under anodic potential. Rather, the active surface for these electrocatalysts can be described as a mixed anionic (hydroxo)chalcogenide surface. The nickel-oxide-coated nickel selenide and nickel telluride samples were prepared through electrodeposition and characterized with various bulk and surface analytical techniques such as powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), line scan analysis, and soft X-ray absorption spectroscopy (sXAS). The electrochemical properties of these oxide-coated chalcogenide surfaces were measured in 1 M KOH under an anodic potential scan and compared with that obtained from pristine nickel selenide and nickel telluride films. It was observed that the electrochemical properties were influenced by the coordinating anion composition and showed a significant difference between oxide, selenide, and telluride surfaces. More importantly, it also revealed that an oxide-coated chalcogenide surface showed a significantly different electrocatalytic response, indicating that electrochemical properties can be an appropriate tool for investigating change in the composition of the chalcogenide surfaces. This study provides conclusive evidence that surface of the nickel-selenide- and telluride-based OER electrocatalysts evolves into a mixed anionic (hydroxo)chalcogenide surface, retaining its predominant chalcogenide coordination

International consensus on patient-centred outcomes in eating disorders

The effectiveness of mental health care can be improved through coordinated and wide-scale outcome measurement. The International Consortium for Health Outcomes Measurement (ICHOM) has produced collaborative sets of outcome measures for various mental health conditions, but no universal guideline yet exists for eating disorders (EDs). This position paper presents a set of outcomes and measures for EDs as determined by 24 international experts from professional and lived experience backgrounds. An adapted Delphi technique was used, and provisional results were validated through an open review survey (n=207). Final recommendations suggest tracking outcomes across four domains: ED behaviours/cognitions, physical health, co-occurring mental health conditions and quality of life/social functioning. These outcomes are captured across three to five patient reported measures per individual. For children, the measures include the Children’s Eating Attitude Test (or for those with ARFID, the Eating Disorder in Youth Questionnaire), the KIDSCREEN-10, and the Revised Children’s Anxiety and Depression Screener-25. For adults, this includes the Eating Disorder Examination Questionnaire (or for ARFID, the Nine-item ARFID Screener), the Patient Health Questionnaire-2/9, the Generalised Anxiety Disorder-2/7, the Clinical Impairment Assessment, and the World Health Organization Disability Assessment Schedule 2.0-12. These questionnaires should be supplemented by information on patient characteristics and circumstances that may impact outcomes (i.e., demographic, historical, and clinical factors, including comorbidities). Adoption of these guidelines on a wide scale will allow comparison of research and clinical intervention so the field can better determine which settings and interventions work best and for whom.SAMHSA -Substance Abuse and Mental Health Services Administration(POCI-01-0145-FEDER-028145