Synthesis and optimisation of IrO2 electrocatalysts by Adams fusion method for solid polymer electrolyte electrolysers

IrO2 as an anodic electrocatalyst for the oxygen evolution reaction (OER) in solid polymer electrolyte (SPE) electrolysers was synthesised by adapting the Adams fusion method. Optimisation of the IrO2 electrocatalyst was achieved by varying the synthesis duration (0.5 – 4 hours) and temperature (250 - 500°C). The physical properties of the electrocatalysts were characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction (XRD). Electrochemical characterisation of the electrocatalysts toward the OER was evaluated by chronoamperometry (CA). CA analysis revealed the best electrocatalytic activity towards the OER for IrO2 synthesised for 2 hours at 350oC which displayed a better electrocatalytic activity than the commercial IrO2 electrocatalyst used in this study. XRD and TEM analyses revealed an increase in crystallinity and average particle size with increasing synthesis duration and temperature which accounted for the decreasing electrocatalytic activity. At 250°C the formation of an active IrO2 electrocatalyst was not favoured

Application of surface-modified metal hydrides for hydrogen separation from gas mixtures containing carbon dioxide and monoxide

Application of surface-modified MH material for H2 separation using temperature/pressure swing absorption–desorption was studied. The substrate alloy had the following composition LaNi3.55Co0.75Al0.4-Mn0.3, and the surface modification was carried out through fluorination followed by aminosilane functionalization and electroless deposition of Pd. The material was found to have good poisoning tolerance towards surface adsorbates, even for the large (rv1.5 kg) batches. Feasibility of its application for H2 separation from gas mixtures (up to 30% CO2 and 100 ppm CO) was demonstrated by testing of a prototype H2 separation system (rv280 g of MH in two reactors), and H2 separation reactor (0.75 kg of MH). The H2 separation was characterized by stable performances in the duration of 250 absorption/desorption cycles. However, the total process productivity was found to be limited by the sluggish H2 absorption (partial H2 pressure 62.5 bar, temperature below 100 °C). In the presence of CO2 and CO, additional deceleration of H2 absorption was observed at space velocities of the feed gas below 5000 hWeb of Scienc

Характеризация сорбционных материалов, содержащих оксиды многовалентных металлов для применения в процессах извлечения лития из солевых растворов

Оскільки літій є одним з найбільш затребуваних матеріалів для виробників електроніки, представляє інтерес розглянути альтернативні джерела його отримання. У статті проаналізовано основні джерела видобутку літію, світові запаси і динаміка його видобутку. Нами розглянута можливість отримання літію з морської води сорбційним методом. Проведена порівняльна характеристика сорбційних матеріалів на основі оксидів багатовалентних металів, визначені параметри їх структури. Методом фазового рентгеноструктурного аналізу встановлено будову сорбентів. Показано, що титан-марганцевий сорбент є композитним матеріалом, що складається з частинок TiO2, рутилу, покритих аморфним MnО2. Методом електронного парамагнітного резонансу встановлено валентний стан марганцевої компоненти в структурі сорбенту. Отримано ізотерми адсорбції літію з розчинів, що моделюють морську воду. Досліджено вплив модифікування сорбційних матеріалів методом іонного апплікування. Показано, що найбільшу сорбційну ємність по іонам Li+ має титан-марганцевий сорбент.Since lithium is one of the most popular materials for the electronics industry, it is of interest to consider alternative sources of its receipt. The article analyzes the main sources of lithium production, global stocks and the dynamics of its production. We have considered the possibility of obtaining lithium from sea water by sorption method. The comparative characteristic of sorption materials based on the multivalent metal oxides was conducted, their structure parameters were determined. By method of X-ray analysis structure of the sorbents was studied. It is shown that the titanium-manganese sorbent is composite material consisting of particles of TiO2, rutile coated with amorphous MnO2. By electron paramagnetic resonance method valence states of manganese component in the sorbent structure were set. Adsorption isotherms from lithium solutions simulating sea water were obtained. The effect of modification of sorption materials by ion application was studied. It is shown that the highest sorption capacity to Li+ ions corresponds to titanium-manganese sorbent.Поскольку литий является одним из самых востребованных материалов для производителей электроники, представляет интерес рассмотреть альтернативные источники его получения. В статье проанализированы основные источники добычи лития, мировые запасы и динамика его добычи. Нами рассмотрена возможность получения лития из морской воды сорбционным методом. Проведена сравнительная характеристика сорбционных материалов на основе оксидов многовалентных металлов, определены параметры их структуры. Методом фазового рентгеноструктурного анализа установлено строение сорбентов. Показано, что титан-марганцевый сорбент является композитным материалом, состоящим из частиц TiO2, рутила, покрытых аморфным MnО2. Методом электронного парамагнитного резонанса установлено валентные состояния марганцевой компоненты в структуре сорбента. Получены изотермы адсорбции лития из растворов моделирующих морскую воду. Исследовано влияние модифицирования сорбционных материалов методом ионного апплицирования. Показано, что наибольшую сорбционную емкость по ионам Li+ имеет титан-марганцевый сорбент

Customization of the Telecommunication Market Based on the Application of the Concept of Service Products

The analysis of the structure and dynamics of the main indicators of the Russian telecommunication services market shows the achievement of saturation state of this market and the exhaustion of extensive sources of growth. Given the presence of a complex of negative socioeconomic factors, the source of maintaining the market positions of telecommunication companies is the customization of the services offered. For this purpose, the concept of the service products can be applied, involving the inclusion of the additional, accompanying and derivative services into the customer service package. The prerequisites for the application of the concept of the service product in the telecommunication field are the availability of the multiattribute properties and interdependence of elements in the product of that field. On the telecommunication market we can consider three types of service products. Customization of the Russian market of telecommunication services is carried out taking into account its strong state protectionism, which is conditioned by the strategic importance and the high social significance of the telecommunication industry. Saturation of the market in the conditions of oligopoly and sophistication of consumers stimulate the telecommunication companies to include in their market offer the service products of all three types

Preparation and Characterization of Sulfonated Poly (ether ether ketone)/Phosphated Zirconia Nanoparticles Composite Proton-conducting Membranes

Proton-conducting membranes of organic–inorganic (sulfonated poly (ether ether ketone)/phosphated zirconia nanoparticles) composite were prepared by incorporating various ratios of phosphated zirconia nanoparticles (ZP) in sulfonated poly (ether ether ketone) (SPEEK). SPEEK/ZP showed an improvement of properties compared with those of the parent SPEEK membrane. Key amongst these is increased proton conductivity to 0.02Scm–1, reduced water uptake to 22 % and reduced methanol permeability to 1.13 × 10–7 cm2 s–1. The methanol permeability was decreased by 28 % compared with SPEEK membrane. It was decreased by one order of magnitude compared with commercial Nafion® 117 (1.39 × 10–6 cm2 s–1).KEYWORDS: Composite membrane, phosphated zirconia, proton conductivity, SPEEK; methanol permeability, direct methanol fuel cell

Performance and Structure of LiNi0.5Mn1.5O4 Prepared from Various Ni Precursors for Lithium Ion Batteries

LiNi0.5Mn1.5O4 compounds were prepared through a solid-state reaction using various Ni precursors. The effect of the precursors on the electrochemical performance of LiNi0.5Mn1.5O4 was investigated. LiNi0.5Mn1.5O4 made from Ni(NO3)2•6H2O shows the best charge-discharge performance. The reversible capacity of LiNi0.5Mn1.5O4 is about 145mAh g–1 and remained at 143mAh g–1 after 10 cycles at 3.0 to 5.0 V. The XRD results showed that the precursors and dispersion method had significant effects on their structures. Pure spinel phase can be obtained with a high energy ball-milling method and Ni(NO3)2•6H2O as precursor. A trace amount of the NiO phase was detected in LiNi0.5Mn1.5O4 with the manual grinding method when Ni(CH3COO)2•6H2O, NiO and Ni2O3 were used as precursors.Keywords: LiNi0.5Mn1.5O

Highly Active, Carbon-supported, PdSn Nano-core, Partially Covered with Pt, as Catalysts for Methanol Oxidation

Carbon-supported, Pt partially covered, PdSn alloy nanoparticles (Pt-PdSn/C) were synthesized via a metathetical reaction of PdSn alloy nanoparticles, and a platinum precursor. The electrochemical activity was evaluated by methanol oxidation. The Pt-PdSn/C catalysts were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammograms (CV). TEM showed that Pt grows layer-by-layer on the surface of PdSn cores and the thickness of the Pt shell is 0.2 nm, about 1–2 monolayers thick. Cyclic voltammetry results showed that PdSn/C nanoparticles, partially covered by Pt, have a better electrocatalystic performance than conventional PtRu/C and PtPdSn/C catalysts. Electrochemical active surface areas of the Pt-PdSn/C was 2.30 times larger than that of PtRu/C and 1.8 times higher than that of PtPdSn/C catalysts. The results showed that a metathetical reaction is an efficient way of preparing, low Pt loading, highly active electrocatalyst, for methanol oxidation, thus offering great potential for producing Pt-based electrocatalyst for direct methanol fuel cells on a large scale.Keywords: Electrocatalyst, fuel cell, methanol oxidation, Pt-decorate

Palygorskite Hybridized Carbon Nanocomposite as a High-Performance Electrocatalyst Support for Formic Acid Oxidation

A nanocomposite, in which acid-treated palygorskite was hybridized with carbon, was prepared and designed as an efficient support for electrocatatlysts. Pd nanoparticles were deposited on the hybrid support as an electrocatalyst for formic acid oxidation. The hybrid supports and electrocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).TEM and XRD results showed that acid treatment had an effective impact on the morphology of palygorskite, but did not destroy its architecture. XPS results indicated that the introduction of palygorskite resulted in a negative shift of binding energy of Pd deposited on it. The electrochemical results showed that the addition of palygorskite into the carbon facilitated the formation of OHads or Oads on the surface of Pd/C-PLS, and further improved the formic acid electrooxidation activity. Therefore, considerable improvements in electrocatalytic activity toward formic acid oxidation was achieved by using this hybrid support when compared with conventional carbon support, suggesting that the introduction of SiO2-based porous palygoriskite was an excellent and cost-efficient way to improve the electrocatalytic performance of carbon support.KEYWORDS Palygorskite, electrocatalyst, composite support, formic acid electrooxidation