Ni3Te2 has been reported as a highly efficient OER electrocatalyst with an overpotential of 180 mV at 10 mA cm−2 and also showing HER catalytic activity in alkaline medium.

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 (E ads) on different catalyst surfaces with the observed overpotential also revealed that this E ads 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.

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 Ni 3 Se 2 and Ni 3 Te 2 surfaces and comparing their electrocatalytic activity with pristine and aged (subjected to a KOH electrolyte for an extended period) Ni 3 Se 2 and Ni 3 Te 2 surfaces, respectively. From such a comparison, it could be confirmed that catalytically active Ni 3 Se 2 and Ni 3 Te 2 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), Xray 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.

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 Ni 3 Te 2 has been reported as a highly efficient electrocatalyst for glucose oxidation, functional at a low operating potential. Ni 3 Te 2 nanostructures were prepared by two synthesis methods, direct electrodeposition on the electrode and hydrothermal method. The electrodeposited Ni 3 Te 2 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 Ni 3 Te 2 , 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 Ni 3 Te 2 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, Ni 3 Te 2 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.

Objective To assess the quality of care in government family planning clinic services in Colombo District.Design Descriptive cross-sectional study.Settings Government family planning clinics in the Colombo District. Study sampleThe study was conducted in 23 government family planning clinics in the Colombo District selected through stratified sampling. 593 women visiting these clinics for family planning services were interviewed and 242 client-provider interactions were observed.Measurements Client exit interviews, observations of service delivery and clinic inventories were used as survey tools to assess the quality in preparedness of the clinics, the service delivery process and client satisfaction, as outcomes of the service. A set of indicators were identified for this purpose.Results The study showed deficiencies in infrastructure, interpersonal relations, privacy, information to clients, especially on side-effects and warning signs, and in the mechanisms to ensure continuity. The majority of clients were satisfied with many aspects of the service such as the family planning method received (94.5%), confidentiality of information shared with the provider (96.1%), competency of provider (97.5%), and physical access to clinics (92.3%). However, many were dissatisfied with the physical conditions of the clinics (>20%), information received (12.5%), opportunity given to discuss their problems with the service providers (18.8%) and waiting times (26.6%).Conclusions Government family planning clinic services need improvement through upgrading of clinic infrastructure, better planning and management of clinic services, regular training of service providers and establishing of a system to monitor service quality.