Electrocatalysts for the hydrogen evolution reaction in alkaline and neutral media. A comparative review

The effect of agarose content on the morphology, phase evolution, and magnetic properties of CoFe2O4 nanoparticles prepared by sol-gel autocombustion method

https://backend.orbit.dtu.dk/ws/files/215280768/1_s2.0_S0360319920312209_main.pdf

MnxCo3-xO4 spinel oxides as efficient oxygen evolution reaction catalysts in alkaline media

Effect of apple cider vinegar agent on the microstructure, phase evolution, and magnetic properties of CoFe2O4 magnetic nanoparticles

Contemporary themes in public policy have emphasised co-productive approaches within both the access and provision of support services to older people. This paper provides a cross disciplinary exploration from its respective authors perspectives on social work and educational gerontology to examine the potential for lifelong learning and learning interventions from which co-production with those using social care services in later life might be better facilitated. Using an example from the UK, we specifically elicit how co-produced care can enhance the horizon of learning and learning research. The synthesis of ideas across these two disciplines could enrich understanding and provide essential levers for moving towards empowerment and emancipation by engaging with a more co-productive approach in social care for older people. (DIPF/Orig.)

http://www.rela.ep.liu.se/issues/10.3384_rela.2000-7426.201672/07/rela_0154.pdf

Mind the gap! An exploration of the role of lifelong learning in promoting co-production and citizenship within social care for older people

Nano-sized cobalt ferrites have been synthesised by novel sol-gel auto combustion route using a mixture of glycine and ammonium nitrate as fuel with stoichiometric ratio of metal nitrates. The materials so obtained, are characterized by X-ray diffraction, scanning electron micrographs and IR data. Preliminary study shows the formation of spinel phase of the material along with some impurity. Cyclic voltammetry and anodic polarization of each oxide have been carried out in the form of electrode on Ni-substrate. The CV curve of each oxide electrode exhibits redox peaks (EPa = 480±12 mV and EPc = 362±6) prior to the oxygen evolution reaction. The anodic polarization curve of each oxide electrode has been recorded in 1 M KOH at 25 °C for the determination of electrocatalytic activity. Among the prepared oxides, the activity is highest with 1.0 mol Co-substitution in Fe3O4 matrix. The most active oxide electrode shows overpotential 503 mV at 100 mA cm current density. Tafel slope values range from 47-59 mV decade. The activation energy has also been estimated by recording the anodic polarization curve at different temperatures.

http://nopr.niscair.res.in/bitstream/123456789/32854/1/IJCA%2054A%2810%29%201221-1225_Suppl%20Data.pdf

Electrocatalytic properties of cobalt ferrites obtained by glycine sol-gel route for oxygen evolution in alkaline medium

Spinel-type pure and Ni-substituted ferrites have been synthesised by novel ammonium hydroxide precipitation method at p H 11.5 and their electrocatalytic properties have been studied with regards to oxygen evolution reaction (OER) in alkaline solutions. Physicochemical and electrochemical techniques used to characterize the materials are X-ray diffraction (XRD), scanning electron microscope (SEM), infrared (IR), cyclic voltammetry (CV) and anodic polarization (Tafel plot). Results of IR and XRD studies show the formation of spinel phase of the material along with some small impurity. All the electrochemical studies are carried out in a three electrode single compartment glass cell. For the purpose, materials have been transformed in the oxide film electrode by oxide slurry painting technique. The cyclic voltammetric curve of each oxide electrode exhibit redox peaks (anodic: 519 ± 33mV and cathodic: 362 ± 2 mV) prior to the oxygen evolution reaction (OER). The electrocatalytic activity of the material has been determined by recording the anodic polarization curve in 1 M KOH at 25°C. Data show that the Ni-substitution in the base oxide enhance the electrocatalytic activity of the material and value is found to be greatest with 0.5 mol Ni. This material produced overpotential 583 mV at 100 mA cm -2 current density. Tafel slope values are ranged between 64-81 mV decade -1 with fractional order of reaction. The activation energy and other thermodynamic parameters are also estimated by recording the anodic polarization curve in 1M KOH at different temperatures.

http://nopr.niscair.res.in/bitstream/123456789/44354/1/IJCT%2025%282%29%20189-195.pdf

Electrocatalytic activity of Ni x Fe 3-x O 4 (0 ≤ x ≤ 1.5) film electrode for oxygen evolution in KOH solutions

Teaching in a traditional face-to-face setting is a very complex activity. The complexity is even further extended when teaching is delivered online or electronically due to the lack of standard cues such as tone of voice, eye contact, body language, and so forth, which are key tools for human communication. Technology-enhanced learning is at the core of using innovative and emerging technologies to facilitate and support learning in both online and blended settings [13]. The success and promotion of effective learning is dependent on a range of factors. The learner’s ability, sound pedagogy, the nature and alignment of the curriculum, assessment, socio-cultural and accessibility issues, and so on [2]. Indeed, the success of technology-enhanced learning is underscored by sound pedagogy and promotion of the effective use of technology in teaching and learning by scholars and practitioners [9]. Drawing on current knowledge, experience, and evidencebased practice from a range of perspectives, ELearning and E-Teaching focuses on Developing skills, teaching, Academic development and assessing online programmes. Applied E-Learning and E-Teaching in Higher Education brings together respected practitioners from across the globe, representing diverse disciplines and perspectives, to share experience, knowledge, current thinking about good practice, and enhancement of the learner experience [14]. The spotlight on the effective integration of pedagogy and technology, the use of technology in teaching research methods at higher degree levels, collaborative learning within multi professional teams, and online communities of inquiry.

The Learning Revolution in Digital Era

Some binary ferrites having molecular formula, MnxFe3-xO4 (0 ≤ x ≤ 1.5) have been synthesized by a simple and cost effective egg white sol-gel route. In each preparation, nitrates of constituent metal were taken as starting materials and egg white as gelling agent. The material, thus obtained was altered in the form of film electrode on the pre-treated Ni- support using an oxide-slurry painting tech-nique and investigated as electrocatalysts for the oxygen evolution reaction in KOH solutions. The study showed that Mn-substitution in the base oxide matrix influences the electrocatalytic activity of the material significantly and found to be greatest with 0.5 mol Mn-substitution. The reaction order has been found to be approximately unity with respect to OH¯ concentration. The Tafel slope values at low potential ranged between ~ 52 and ~ 65 mVdecade-1. The thermodynamic parameters namely, standard apparent electrochemical enthalpy of activa-tion (), standard enthalpy of activation () and standard entropy of activation () for the oxygen evolution reac-tion (OER) have also been determined. It has been observed that and values decreased with Mn-substitution in the Fe3O4 lattice. This decrease inandwas found to be greatest with 0.5 mol Mn. Thevalues were also found to be highly negative varying between ~ - 185 and – 211 J deg-1 mol-1.

Electrocatalytic Properties of Egg-white Sol-gel Derived MnxFe3-xO4 (0 ≤ x ≤ 1.5) for Alkaline Water Electrolysis

Some ternary ferrites having composition CoxNi1.5-xFe1.5O4 (0.0 ≤ x ≤ 1.25) have been synthesized by NH4OH co-precipitation method at 11.5 pH. Materials, so obtained, were tested for their electrocatalytic properties towards oxygen evolution reaction (OER) in the form film on Ni-support in alkaline solution. The study showed that the electrocatalytic properties the material increased with partial substitution of Co for Ni in the base oxide (Ni1.5Fe1.5O4). The value being highest with 0.5 mol Co-substitution. At E = 850 mV vs Hg/HgO in 1M KOH at 25 oC, the electrode showed apparent current density 206.2 mA cm-2, which is about 3 times higher than the base oxide. The Tafel slope values were ranged between 46-82 mV decade-1. A pair of redox peak, an anodic (EPa = 522±28 mV) and corresponding cathodic (EPc= 356±9 mV), was observed in the cyclic voltammetry (CV) study of the material. The thermodynamic parameters namely, standard apparent electrochemical enthalpy of activation ( ), standard enthalpy of activation ( ) and standard entropy of activation ( ) for the oxygen evolution reaction (OER) have also been determined by recording anodic polarization curve in 1M KOH. The value of  was observed to be almost similar with each oxide electrode. The  values were highly negative and ranged between ~ -165 and ~ -207 J deg-1 mol-1. Phase and morphology of materials have been investigated by using physical techniques X-ray diffraction, infrared spectroscopy (IR) and scanning electron microscope (SEM), respectively.

Ritu Yadav

Papers

Electrocatalytic properties of cobalt ferrites obtained by glycine sol-gel route for oxygen evolution in alkaline medium

Electrocatalytic activity of Ni x Fe 3-x O 4 (0 ≤ x ≤ 1.5) film electrode for oxygen evolution in KOH solutions

The Learning Revolution in Digital Era

Electrocatalytic Properties of Egg-white Sol-gel Derived MnxFe3-xO4 (0 ≤ x ≤ 1.5) for Alkaline Water Electrolysis

Effect of Co-substitution on the electrocatalytic properties of Ni1.5Fe1.5O4 for oxygen evolution in alkaline solutions