Energy consumption in the electrolytic evolution of hydrogen with iron-nickel electrodes

The possibilities to reduce energy consumption in the electrolytic hydrogen production using ionic activators added into an alkaline electrolyte have been investigated. Two cathode/anode systems, Fe/Ni and Ni/Fe were investigated. We have found that some activators, like tris-(ethylenediamine)Co(III) chloride complex in combination with the sodium molybdate can reduce energy needs per mass unit of hydrogen produced for more than ten percent in all investigated systems compared to those of non-activated electrolytes. Additionally, iron exhibits some special properties in this view.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Microwave assisted electrolysis of alkaline water solution

The effect of microwaves (MW) on the electrolytic process of 6M KOH water solution is investigated in the temperature range from 291 K to 337 K. At lower temperatures, microwaves facilitate electrolytic process, whereas the effect is reversed at higher temperatures.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Porous ceramics based on natural mineral sources

Starting raw materials, clay and diatomite, from coal mine Kolubara, Serbia were purified using heat and chemical treatment. Porous silica ceramics were obtained at low forming pressure (40-80 MPa) and low sintering temperature (1000-1300 °C) in air. Boric acid as a /ow-cost additive was used. Sintered samples have average pore si:ze diameters ranging of macroporous for clay 0.1-10 μm and for diatomite 0.05-5 μm. As-received and the obtained samples were characterized by XRD, SEM and mercury porosimetry measurements. Relations between mechanical characteristics of samples formed at different temperature were studied

Co/Mo bimetallic carbides with potential applications as catalyst support in pem fuel cells - synthesis and characterization

Co/Mo carbides were prepared by co-impregnation with aqueous solution of metal salts and sucrose into ordered mesoporous SBA-15 silica template using carbothermal hydrogen reduction. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDS) . Electrochemical characterization of obtained materials was performed by cyclic voltammetry in acide solution. Bimetallic CoMo carbide obtained by using carbothermal hydrogen reduction of Co Mo precursors is formed when the Co/Mo molar ratio is 1.0

Synthesis and characterization of co-mo bimetallic carbides

Co-Mo carbides were prepared by impregnation with aqueous solution of metal salts and sucrose into ordered mesoporous SBA-15 silica template using carbothermal hydrogen reduction. Bimetallic Co-Mo carbide obtained by using carbothermal hydrogen reduction of Co-Mo precursors is formed when the Co-Mo molar ratio is 1.0. The obtained samples were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. Electrochemical characterization of obtained materials wеre performed by cyclic voltammetry in acid solution

Investigation of tungsten-carbide-oxideas the anode catalysts supports for the proton exchange membrane fuel cells

A significant research efforts are directed towards the development of compact energy supply devices, so-called stacks of fuel cells, which might be located near or at the point of energy consumption. For widespread use, the most practical are fuel cells with proton exchange membrane, which produce clean electricity, heat and water, at low temperatures. The price of the catalyst limits the mass production and large-scale utilization of fuel cells. Within our research, non-stoichiometric tungsten-carbide-oxide (WxCyOz) were developed as support for catalysts based on PtRu for PEM fuel cells. The conductivity, morphology and structure of the synthesized catalysts were investigated. Cyclic voltammetry, linear scan voltammetry and rotating disk electrode voltammetry were used to determine performance of obtained PtRu/WxCyOz catalysts. Special attention was given to the analysis of CO poisoning. The catalyst with the best performance (30% PtRu/WxCyOz) has higher number of active sites for HOR and the highest interfacial region which contributes the improved CO tolerance, in relation to the other tested catalysts. By testing this catalyst as an anode catalyst in a single PEM fuel cell, a significantly lower power drop was obtained (16,3%) compared to a single fuel cell that uses commercial catalysts (35,3%). These results highlight the potential of PtRu/WxCyOz catalysts in mitigating performance degradation caused by CO poisoning in PEM fuel cells

Enhanced Catalytic Activity and Energy Savings with Ni-Zn-Mo Ionic Activators for Hydrogen Evolution in Alkaline Electrolysis

Green hydrogen produced by alkaline electrolysis is a promising solution to address the world’s increasing energy demand while mitigating greenhouse gas emissions. However, the efficient and cost-effective production of green hydrogen via alkaline electrolysis requires improvements. This paper presents an in situ activation process that simplifies the alkaline electrolysis technology while enhancing the catalytic activity of electrodes for the hydrogen evolution reaction. The aim of this research is to enhance the energy efficiency of alkaline electrolysis and decrease the energy consumption for hydrogen production. To achieve this goal, ionic activators comprising Ni, Zn, and Mo were incorporated into the standard electrolyte solution. Our results demonstrate that the anticipated improvement in the catalytic activity of the d-metal combination, surpassing even that of precious metals, has been successfully attained. As a result, a 20% reduction in energy consumption (REC) for the hydrogen produced has been observed. The catalytic activity of the added activators for the hydrogen evolution reaction was discussed by analyzing the mechanism of the reaction via Tafel analysis and EIS techniques. These findings offer a promising approach to improve alkaline electrolysis and enhance the production of green hydrogen

Enhancement of the electrocatalytic activity of Ni electrode for hydrogen evolution by electrodeposited V and Co on its surface

Enhancement of the electrocatalytic effect of Ni electrode for hydrogen evolution reaction (HER) by co-electrodeposited V and Co at metallic Ni (Ni-V-Co) was studied by using quasi-potentiostatic polarization technique from 1 M KOH at 25 ºC. The obtained exchange current density for HER with Ni-V-Co electrode, (5.5x10-4 Acm-2), is about two orders of magnitude higher than for metallic Ni electrode. The results suggested the existence of the synergetic effect of V and Co deposit on the catalytic activity of Ni electrode for HER. By using X-ray fluorescence (XRF) analysis the presence of Co and V at metallic Ni support was proved.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Determination of the BTEX compounds in building materials and waste samples containing mineral oils as the main component using Headspace GC/FID

BTEX jedinjenja su lako isparlјiva aromatična jedinjenja, klasifikovana kao toksična jedinjenja i kao takva su opasna po zdravlje ljudii životnu sredinu. Predmet istraživanja u ovom radu su BTEX jedinjenja u uzorcima građevinskog materijala sa mineralnim uljima kao glavnom komponentom. S obzirom da su ona sastavni deo mineralnih ulja, važno je odrediti njihovo prisustvo, koncentraciju i dalju distribuciju u životnu sredinu. Tokom eksperimentalnog istraživanja, ispitivan je sadržaj BTEX jedinjenja: benzen, toluen, ksilen (o, p, m) i etilbenzen u uzorcima mineralnih ulja iz građevinskih materijala i otpada. Metoda za određivanje ovih jedinjenja, kao i za njihovu kvantifikaciju u uzorcima mineralnih ulja, razvijena je u Laboratoriji za fizičku hemiju, Instituta za nuklearne nauke „Vinča“, Univerziteta u Beogradu, modifikacijom i unapređenjem standardnih metoda[1, 2]. Za potrebe ovog istraživanja,u eksperimentalnom delu, primenom Headspace ekstrakcije sa GC-FID tehnikom, određen je kvalitativni i kvantitativni sadržaj BTEX jedinjenja, što istovremeno predstavlja i validaciju ispitivane metode, kao i određivanje njene merne nesigurnosti (Tabela 1.).Parametri za validaciju ove metode su bili: specifičnost, linearnost, granica detekcije (LOD), granica kvantifikacije (LOQ), ponovljivost i tačnost svakog jedinjenja. Primenom opisane metode postignuta je pouzdana identifikacija ispitivanih jedinjenja. Identifikacija se ostvaruje poređenjem retencionih vremena ispitivanih jedinjenja sa retencionim vremenima analitičkih standarda. FID detektor pokazuje linearan odgovor u opsegu 0,1 do 10 µg , odnosno R ≥ 0,99. Vrednosti standarda na kalibracionoj krivi su potvrdili preciznost metode. Relativna standardna devijacija RSD je ispod 5%, što dokazuje da je metoda tačna i reproduktivna [3-8]. Predstavljena metoda je validirana kao pouzdana, precizna i tačna za potrebe kontrole kvaliteta mineralnih ulja koja su korišćena ili će se koristiti u toku izgradnje građevinskih objekata, kao i za otpadni materijal.8th Symposium Chemistry and Environmental Protection : May 30 - June 1, Kruševac, 2018

Ab Initio Study of Graphene Interaction with O-2, O, and O-

A systematic ab initio (DFT-GGA) study of adsorption of various oxygen species on graphene has been performed in order to find out general trends and provide a good starting point to analyze the oxidation of more complex carbon materials. Particular attention was paid to finding an appropriate supercell model. According to our findings, atomic O is characterized by stable adsorption on graphene and very strong adsorption on defective graphene. On the other hand, O-2 does not adsorb on graphene and is allowed to diffuse freely to the defect, where it is expected to dissociate into two strongly adsorbed O atoms. The obtained results were compared with available theoretical data in the literature and good agreement was achieved