Electrodeposition of NiMo alloy coatings and their characterization as cathodes for hydrogen evolution in sodium hydroxide solution

The hydrogen evolution reaction on electrodeposited NiMo alloy coatings, as well as their electrochemical properties in NaOH solutions have been investigated by polarization measurements, cyclic voltammetry and EIS technique. It is shown that NiMo alloy coatings electrodeposited from pyrophosphate-sodium bicarbonate bath possess high catalytic activity for hydrogen evolution in NaOH solutions. Their stability in 1M NaOH at 25 0C under the condition of reverse polarization is shown to be very good, while in 33% NaOH at 850C (conditions of industrial electrolysis) electrodeposited NiMo alloy coatings exhibit also high catalytic activity, but low stability, as a consequence of massive dissolution of alloy coatings under the condition of reverse polarization

Cost effective alloys based catalysts for alkaline fuel cells application

Alkaline fuel cells (AFCs) have recently become attractive as environmental friendly future power sources. It was really important having in mind that in alkaline media less expensive non noble catalysts could be used. Namely, successful alkaline anion exchange membrane development enabled benefits of faster kinetics of oxygen reduction reaction in alkaline solutions. In this study electrodeposited silver-palladium alloys of various composition were investigated and tested as the prospective catalysts for direct ethanol fuel cells application. All samples were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, as well as by electrochemical techniques: cyclic voltammetry, polarization measurements at rotating disc electrode. The electrochemical active surface area was determined from the charge values corresponding to the reduction of Pd (II) oxide, assuming 420 μC for full oxide monolayer coverage. The optimal alloy composition showing the best catalytic activity for oxygen reduction and ethanol oxidation, with as much as possible lower content of Pd, was determined. It was found that it could be possible to obtain alloys containing only ~ 20% of more noble metal – palladium, showing high activity for both anode and cathode reaction. The stability testing gave very promising results, as well

On the kinetics of the hydrogen evolution reaction on Ni-MoOx composite catalysts in alkaline solutions

MoO3 particles were co-deposited with Ni onto smooth or rough Ni supports from modified Watt’s baths of different compositions. Morphology and composition of the electrodeposits were characterized by means of cyclic voltammetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic activity of the composite catalysts for H2 evolution in alkaline solutions was determined by quasi-stationary polarization curves. Activity increases with MoOx content in the Ni deposit up to a limiting value. Composite Ni-MoOx catalyst performed high catalytic activity, similar to that of commercial Ni-RuO2 catalyst. Stability tests showed that Ni-MoOx codeposits are stable under condition of constant current and exhibit excellent tolerance to repeated short-circuiting

Ni-MoO2 composite cathodes for hydrogen evolution in alkaline solution: Effect of aging of the electrolyte for their electrodeposition

In this work the effect of aging of the electrolyte for electrodeposition of Ni-MoO2 composite coatings on their morphology (scanning electron microscopy), chemical composition (energy-dispersive X-ray spectroscopy), polarization characteristics and the “service life” test performance for the hydrogen evolution reaction (HER) in 32 mass % NaOH at 90°C was investigated. Polarization characteristics and results of the “service life” test of Ni-MoO2 composite coatings obtained after different aging periods of the electrolyte for deposition (suspension of MoO2 powder particles in the solution containing 2 M NH4Cl + 0.2 M NiCl2) were compared with that recorded for De Nora’s commercial Ni+RuO2 cathode coating (DN). It was shown that aging of the electrolyte did not influence the morphology and chemical composition of Ni-MoO2 composite coatings electrodeposited under simulated conditions for their industrial production, while polarization characteristics for the HER were influenced. The best coating, obtained after 180 days of the electrolyte aging, showed completely different (layered) structure of the deposit and significantly better performance than the commercial DN electrode during the “service life” test. [Projekat Ministarstva nauke Republike Srbije, br. 172054

Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part I: Hydrogen evolution

The hydrogen evolution reaction (HER) was studied at electrodeposited Ni and Ni-(Ebonex/Ir) composite coatings in 1 mol dm-3 NaOH solution at 25 °C. The Ni-(Ebonex/Ir) coatings were electrodeposited from a nickel Watts type bath containing different amounts of suspended Ebonex/Ir(30 wt.%) powder particles (0-2 g dm-3) onto a Ni 40 mesh substrate. The electrodes were investigated by cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), electrochemical impedance spectroscopy (EIS) and polarization measurements. It was shown that the roughness factor of coatings increased to a maximum value of 27 with increasing the concentration of Ebonex/Ir particles in the deposition bath, while that of a pure Ni coating was found to be 3.2. In the whole potential range of the HER only one Tafel slope of about -120 mV dec-1 was observed at all polarization curves. Considerably improved intrinsic catalytic activity for the HER compared to pure Ni was achieved with the composite coating deposited from the bath with the lowest concentration of Ebonex/Ir particles (0.1 g dm-3). Further enhancement of the apparent catalytic activity for the HER of Ni-(Ebonex/Ir) composite coatings obtained at higher concentrations of suspended Ebonex/Ir particles in the bath was attributed only to the increase of their electrochemically active surface area. © 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Paracelsus a pioneer of emergency medicine and surgery, the father of toxicology and pharmacology, the precursor of homeopathy and chemotherapy

In the entire constellation of doctors, pharmacists, physicists, alchemists, anatomists, pioneers of medicine, there are few who have left as much controversy behind as Paracelsus did. Paracelsus' real name was Theophrastus Philippus Aureolus Bombastus von Hohenheim and he was essentially an alchemist, physicist, astrologer and practiced the occult. His medical practice introduced numerous revolutionary treatments for that time, although many contemporaries considered his works to be a collection of superstitious and repulsive folk remedies. He wrote: "If you prevent the infection, nature will heal the wound on its own." This treatment brought him fame in the circles of Western medicine. He was also the first to introduce the use of various chemicals and minerals in treatment o illnes, the first to give the name zinc and introduced tin powder as an anthelmintic. In long ago 1530 Paracelsus wrote a clinical description of syphilis, in which he claimed that the disease could be successfully treated with orally, carefully measured doses of mercury compounds. During his stay in the mines holles, he wrote that the "miner's disease" (silicosis) was caused by inhaling metal fumes and that it was not a punishment for the sin used by mountain spirits. The first stated that, if given in small doses, "what makes a person sick also cures him" - expectation of the modern practice of homeopathy. It was written that Paracelsus cured many plague-stricken people in the city of Stertzing in the summer of 1534 by giving an oral tablet made of bread and secretion from the pustule. Paracelsus is often referred to as the father of toxicology. In that sense, his sentence is especially significant: "All things are poisonous and nothing is without poison; it's just the dose that makes a thing not poison." This remains the basic principle of toxicology to these days. Although he is often called a quack doctor, he is rightly among the 100 most influential scientists in all of human history

Corrected accelerated service life test of electrodeposited NiSn alloys and Ni as cathodes for industrial alkaline water electrolysis

The "corrected accelerated service life test for hydrogen evolution reaction" (CASLT-HER), designed for application of certain electrode materials as cathodes in the cell for alkaline water electrolysis in 30 % KOH at 80 degrees C, was performed at electrodeposited NiSn alloy and Ni 40 mesh electrodes. The Ni 40 mesh was slightly etched, while the NiSn alloy coating was electro-deposited from the bath containing pyrophosphate, glycine, SnCl2 and NiCl2 onto Ni 40 mesh to the thickness of approximately 40 mu m. It is shown that the NiSn cathode possess from maximum 0.77 V to minimum 0.30 V better over-potential than the Ni 40 mesh electrode during the 5 years of their exploitation at the conditions of industrial alkaline water electrolysis. It is also shown that both electrodes should be held at j = -0.3 A cm(-2) for at least 5 h in order to establish stable overpotential response. The limiting overpotential values for applying cyclic voltammetry (CVs, to mimic "polarity inversion") should be determined in a separate experiment before the CASLT-HER and should be adjusted during the application of CVs

Uticaj farmakološki aktivnih jedinjenja iz ekstrakta Ginkgo bilobae na kontraktilnost duodenuma i ileuma kunića

Findings that there are pharmacologically active compounds in the Ginkgo bilobae extract recently provoked numerous investigations of their action on the receptors of the autonomous nervous system. The purpose of the present study was to determine the influence of gingko extract on the contractility of the longitudinal smooth muscle layer in the wall of the rabbit duodenum and ileum using the method of Magnus. Results clearly show that gingko extract causes a dose dependent tonus decrease of duodenal and Heal smooth muscles in the rabbit. It also reduces the stimulation of spontaneous activity of smooth muscles caused by acetylcholine, the reduction being greater in ileum compared to duodenum.Biohemijska saznanja o prisustvu farmakološki aktivnih jedinjenja iz ekstrakta Ginkgo bilobae, dala su nov podstrek za izučavanje njihovog dejstva na receptore autonomnog nervnog sistema. Otuda je cilj našeg istraživanja bio da se ispita uticaj ekstrakta ove biljke na kontraktilnost glatkomišićnog sloja u zidu duodenuma i ileuma kunića metodom po Magnus-u. Rezultati Istraživanja ukazuju da ispitivani ekstrakt izaziva dozno-zavisno sniženje tonusa longitudinalne glatke muskulature duodenuma i ileuma, kao i da redukuje acetilholinom izazvanu stimulaciju spontane aktivnosti duodenuma i ileuma

Enhancement of Electron-Phonon Coupling in Alkali-Doped Graphene and Thin MgB2 Layers

We present first principle investigation of enhancement of the electron-phonon coupling of superconducting alkali-doped graphene (e.g. LiC6-mono) and thin layers of MgB2 using density functional theory (DFT). These systems resemble in many ways, not only in geometry but as well as in electronic structure. Namely, like in alkali-C6, where we have carbon hexagons with alkali adatom in the hollow site, in MgB2 there are boron hexagons with Mg in hollow site. For instance, both theoretical and experimental studies of LiC6-mono proved a possibility of superconductivity in doped graphene. Continuing this investigation, we explored an enhancement of electron-phonon coupling and the raise of critical temperature in LiC6-mono. Inspired by similarity of intercalated graphite with MgB2, we studied the electron-phonon coupling in MgB2 thin films. We used ab-initio calculations of phonon dispersion and electron-phonon-coupling within framework of DFT using Quantum Espresso. Our research included dopant and strain effects on an enhancement of electron-phonon coupling. We demonstrated an increase of electron-phonon coupling and critical temperatures

Accelerated service life test of electrodeposited NiSn coatings as bifunctional hydrogen and oxygen evolution catalysts for alkaline water electrolysis

Electrodeposited NiSn alloy coatings were tested for application as cathodes and anodes in the cell for alkaline water electrolysis in 30 wt.% KOH at 80 ºC. The "accelerated service life test" (ASLT) was performed for HER and OER reactions, and compared to those for Ni electrode. The morphology and chemical compositions of the NiSn and Ni coatings were investigated by SEM and EDS, while their surface composition was investigated by XPS before and after the ASLT for both reactions, respectively. It was shown that the cell voltage at j = 0.3 A cm-2 saving with the NiSn electrodes amounts to about 435 mV before and about 304 mV after the ASLT. SEM results showed that no changes in the morphology of as prepared samples could be detected after the ASLTs for both reactions. EDS and XPS analysis confirmed that some changes occurred during the ASLT, particularly for the oxygen content in the surface layer. This work was financially supported by Ministry of Education, Science and Technological Development Republic of Serbia, under Contract No. 172054. he authors would like to acknowledge networking support by the COST Action MP1407