Today’s energy concerns require the development of suitable solutions for the storage of energy from renewable resources. Although the chemical storage of energy using molecular hydrogen as energy carrier is one of the best options, this type of energy storage requires the conversion of hydrogen to liquid organic hydrogen careers (LOHCs) for practical reasons. This goal is challenging and highly desirable at the same time. In comparison to dihydrogen, hydrogen storage in LOHCs offers easier handling and minimum dangers involved in their production, storage, and reconversion. To achieve efficient processes based on LOHCs highly active catalyst systems are required which ideally are based on cheap and abundant metals such as iron. This review summarizes recent advances in ironcatalyzed hydrogenation and dehydrogenation reactions, with relevance to reversible hydrogen storage in small molecules. It entails the dehydrogenation reactions of formic acid and methanol water mixtures, the reverse reaction, the hydrogenation of CO2, dehydrogenation of alcohols, and the hydrogenation of different carbonyl compounds as the formal reverse reaction, as well as hydrogenation and dehydrogenation reactions of N-heterocyclic compounds and hydrogen release reactions from amino boranes.
In this work preparation and characteristic of modified nanocarbons is described. These materials were obtained using nanocrystalline iron as a catalyst and ethylene as a carbon source at 700°C. The influence of argon or hydrogen addition to reaction mixture was investigated. After ethylene decomposition samples were hydrogenated at 500°C. As a results iron carbide (Fe3C) in the carbon matrix in the form of multi walled carbon nanotubes was obtained. After a treatment under hydrogen atmosphere iron carbide decomposed to iron and carbon and small iron particles agglomerated into larger ones.
Here, we report the results of screening of the catalytic activity of Pd-containing chitosan beads and cryogels in the cross-coupling reaction, hydrogenation of alkenes, nitro-, and carbonyl compounds and the hydrodechlorination of chlorophenols. Pd0-containing chitosan beads and cryogels show moderate catalytic activity in the reduction of alkenes and nitroaromatics. The conversion of nitroaromatics decreases for substrates with electron-withdrawing substituents, while the conversion of alkenes increases with the activation of carbon-carbon double bonds. For several substrates, a significant difference in kinetics and conversion degrees was observed for Pd nanoparticles supported on chitosan beads and cryogels. It was found that conversion in the hydrodechlorination reaction depends on substrate structure, being higher for substrates containing substituents with a positive mesomeric effect. Pd2+-chitosan catalysts showed high catalytic activity in cross-coupling (Heck reaction) offering the following advantages over known catalytic systems: lower reaction temperature, the selective functionalisation of C-I bonds, and the possibility to perform reactions with iodobenzene without base addition.
The paper presents the results of the influence of electrolytic hydrogenation on the change of electrochemical properties of selected stainless steels and their susceptibility to the formation of galvanic hydrogen. It has been shown that the electrolytic hydrogenation of steel X5CrNi18-10 and X6Cr17 in the state of delivery, not only changes their corrosion resistance, but also contributes to the formation of galvanic hydrogen cells.
PL
Przedstawiono wyniki badań wpływu elektrolitycznego wodorowania na zmianę właściwości elektrochemicznych wybranych gatunków stali nierdzewnych oraz podatności ich do tworzenia galwanicznych ogniw wodorowych. Wykazano, że elektrolityczne wodorowanie stali X5CrNi18-10 i X6Cr17 w stanie dostawy powoduje zmianę ich odporności korozyjnej, ale także przyczynia się do powstawania galwanicznych ogniw wodorowych.
The problems of synthesis of Ni-Mo, Ni-Mo Co and Co-Mo oxide catalysts for hydrodesulfurization and hydrogenation of aromatic hydrocarbons in the composition of kerosene, diesel and oil fractions are discussed. The influence of spent adsorbent and kaolin as the additives on the physical-chemical and catalytic properties of bimetallic and trimetallic catalysts is established.
This paper presents a generalized approach to the mechanisms of oxidation, hydrogenation and nitriding of metals under ion irradiation with reactive particles at elevated temperatures. Experimental results on the plasma oxidation of bilayered Y/Zr films, the plasma hydrogenation of Mg films and the ion beam (1.2 keV N2+) nitriding of stainless steel are presented and discussed. We make special emphasis on the analysis of surface effects and their role in the initiation of mixing of bilayered films, the ingress of reactive species in the bulk and the restructuring of the surface layers. It is suggested that primary processes driving reactive atoms from the surface into the bulk are surface instabilities induced by thermal and ballistic surface atom relocations under reactive adsorption and ion irradiation, respectively. The diffusion of adatoms and vacancies, at temperature when they become mobile, provide the means to relax the surface energy. It is recognized that the stabilizing effect of surface adatom diffusion is significant at temperatures below 300–350°C. As the temperature increases, the role of surface adatom diffusion decreases and processes in the bulk become dominant. The atoms of subsurface monolayers occupy energetically favorable sites on the surface, and result in reduced surface energy.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.