Pd-Ir alloy as an anode material for borohydride oxidation

A Pd-Ir alloy (1:1) coated on microfibrous carbon (11 μm diameter) supported on a titanium plate was evaluated as an electrode for the anodic oxidation of borohydride. The hydrogen generated, due to the parallel reaction of borohydride hydrolysis, was measured during the electrolysis obtaining less than 0.1 cm 3 min -1 H 2 between -1 and 0 V vs. Hg/HgO (-0.86 and 0.14 V vs. SHE), while the current densities for the oxidation of borohydride were up to 367 mA cm -2 in 0.5 mol dm -3 NaBH 4 + 3 mol dm -3 NaOH. The low rate of hydrogen generation suggests that Pd-Ir could be a promising catalyst for borohydride oxidation. However, higher rates of hydrogen were generated at the open circuit potential, which is inconvenient in the direct borohydride fuel cell. Cyclic voltammetry allowed analysis of the oxidation peaks due to the borohydride oxidation. To obtain a further understanding of the borohydride oxidation mechanism at Pd-Ir electrodes, density functional theory (DFT) was used to examine the reaction mechanism at Pd 2 -Ir 1 (111) and Pd 2 -Ir 2 (111) surfaces. The competition between borohydride oxidation and hydrogen evolution on the Pd-Ir alloys is compared with that on pure Pd(111), suggesting that the presence of Ir favors borohydride oxidation rather than hydrogen evolution. © 2014 Elsevier B.V. All rights reserved

Electrocatalyst Design for Direct Borohydride Oxidation Guided by First Principles

© 2017 American Chemical Society. Density functional theory (DFT) calculations are used to propose a Au-Cu binary metal catalyst for the electrochemical borohydride oxidation reaction (BOR), which is evaluated experimentally and observed to show enhanced oxidation activity relative to a pure Au electrode. Our previous work has applied DFT methods to determine the BOR mechanism and elucidate the key reaction steps that dictate catalyst activity and selectivity to complete oxidation. A balanced initial adsorption strength of the borohydride anion is essential for an active and selective catalyst. Adsorption must be strong enough to provide a reasonable coverage of surface species and promote B-H bond dissociation but not so strong as to promote easy dissociation and provide a high coverage of surface H atoms that result in H 2 evolution. Borohydride adsorption energetics were evaluated for a series of close-packed pure metal surfaces. Copper catalysts appear encouraging but are not electrochemically stable under reaction conditions. Gold-copper alloys are predicted to show increased activity compared to a pure gold electrode while maintaining the selectivity to direct oxidation and increasing the stability compared to pure Cu. DFT results suggest an approximately 0.2 V decrease in the overpotential for borohydride oxidation on a Au 2 Cu(111) electrode compared to that on a Au(111) electrode. This DFT-predicted reduction in overpotential is realized experimentally. Electrodeposition was used to prepare AuCu electrodes, and their borohydride oxidation electrokinetics were examined by linear sweep voltammetry. An 88.5% gold and 11.5% copper sample demonstrated an overpotential reduction of 0.17 V compared to a pure Au electrode. The binding energy and adsorption free energy of BH 4- over other surface alloys are also examined to further identify promising BOR electrodes. (Chemical Equation Presented)

Phenology of Pistacia atlantica Desf subsp. mutica (F. & M.) Rech. at Khalkhal forests

Phenological characteristics of Pistacia atlantica Desf subsp. Mutica (F. & M.) Rech were investigated at two different sites of Khalkhal Forests (Mazrae and Kandiragh) at two altitudes (1450 and 1650 m.a.s.l) and one aspect (south), during the years of 2001 to 2003. For this study, 30 trees at each site were selected and registered. The study started at March (beginning of the growing season) and ended at full leaf fall of each year. Every 7-10 days, the phenological characteristics were measured as date of budding, date of leaf formation, flowering, fruiting, fruit ripening and leaf fall. Statistical analaysis was done by compound analysis of variance method. Results showed that date of budding is between 3rd and 4th week of April, flowering between 4th week of April and 1st week of  May, fruit set between 2nd and 3rd week of May, fruit ripening between 4th week of October and 1st week of November and leaf fall between 1st and 2nd week of December. The statistical analysis showed that there were significant differences beween the phenological characteristics and two altitudes. There was significant negative correlations between average rainfall and date of budding and flowering

Effect of Growth Promoting Rhizobacteria on growth and nutrient elements of common hazelnut (Corylus avellana L.) seedlings in Ardabil Fandoqlou nursery

The aim of present research was to investigate the effects of Growth Promoting Rhizobacteria on growth (height, collar diameter, dry weight of root and shoot, total dry biomass and quality index of seedling) and nutrient absorption (N, P, K, Fe and Zn) in leaf of common hazelnut (Corylus avellana L.) For this purpose, effects of three bacteria including Pseudomonas putida, Bacillus subtilis and Enterobacter cloacae, alone and together, for 7 months on filbert seedling in pots containing of autoclaved soil under nursery conditions were evaluated. The results showed that the greatest height (26.88 cm), collar diameter (7.17 mm), leaf area index (23.87 cm2/g) and N concentration (2.81%) were observed for seedlings inoculated with all bacterial. The biggest root dry weight, root volume, seedling quality index and P concentration were observed in seedlings inoculated with P. putida (alone). The highest Fe and Zn were obtained in seedlings inoculated with B. subtilis and P. putida, respectively. Generally, according to beneficial effects of Growth Promoting Rhizobacteria on absorption of nutrient elements and morphologic growth, P. putida, B. subtilis and E. cloacae are recommended for seedling inoculation, respectively. In fact, inoculation of root with Growth Promoting Rhizobacteria (root engineering) can be an appropriate approach to produce healthy and strong seedlings in nursery and increasing success of plantation in disturbed and degraded habitats

The Effect of Educational Intervention with Mobile Health Technology on COVID-19 Induced Stress among Pregnant Women: A Randomized Controlled Trial

Background & aim: The spread of COVID-19 has increased the stress level in pregnant women. The present study was performed to determine the effect of a mobile-based health educational intervention on the stress induced by the COVID-19 pandemic among pregnant women.Methods: This randomized controlled trial study was carried out on 80 pregnant women (40 sampleintervention and 40 control) referred to Gonabad Comprehensive Urban Health Service Centers from October to December 2021 who were selected using stratified random sampling. Data collection tools included demographic questionnaire (12 questions) and the valid and reliable questionnaire of the Corona Stress Scale (CSS-18). The questionnaires were filled out through self-administered method svia the Porsline platform in three stages: before, immediately after, and one month after the intervention. The intervention group received five 30-minute education sessions as twice a week based on the latest Ministry of Health maternity and neonatal health guidelines. The control group received educational content in PDF format. Data were analyzed by Wilcoxon, Benferroni, Mann-Whitney, and independent t-tests using SPSS (version 16).Results:  The mean COVID-19 stress score before the intervention was not statistically significant in the two groups (P= 0.92). After the intervention, the mean stress score of COVID-19 in the intervention group was estimated 48.12 ±12.24, which was significantly lower than the control group (57.02 ± 15.99) (P˂0.001).Conclusion: Mobile-based education intervention reduces COVID-19 stress in pregnant women. It is suggested that this approach be implemented for the provision of healthcare to pregnant women during the COVID-19 pandemic

Pomegranate (Punica granatum) Peel Extract as a Green Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

The inhibition effect of pomegranate peel extract (PPE) on the corrosion of mild steel in hydrochloric acid (HCl) solution was investigated. The polarization, mass loss, and electrochemical impendence techniques were used to evaluate the corrosion inhibition performance of the pomegranate peel extract. The results revealed that PPE acts as a corrosion inhibitor in HCl solution. The inhibition efficiency increased with the increase of extract concentration. The inhibition action was attributed to the adsorption of the chemical compounds present in the extract solution, on mild steel surface

Insights into the borohydride electrooxidation reaction on metallic nickel from operando FTIRS, on-line DEMS and DFT

International audienceDirect Borohydride Fuel Cells (DBFCs) are considered as promising power sources for portable and mobile applications. Their advantages are high theoretical energy density, and high theoretical cell voltage. Metallic Ni has recently emerged as a promising electrode material for DBFCs. In this work we combine electrochemical, operando Fourier-Transform infrared spectroscopy (FTIRS), and online differential electrochemical mass spectrometry (DEMS) measurements with density functional theory (DFT) calculations to advance the understanding of the borohydride oxidation reaction on Ni