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The development of low-cost and safe hydrogen storage systems is a priority when creating new energy sources. Storing hydrogen in chemical compounds in which it occurs naturally is the only alternative. Aromatic hydrocarbons, capable of reversible hydrogenation–dehydrogenation reactions, are of the greatest interest among regenerated hydrogen-containing compounds and can be used for hydrogen storage. Naphthalene, its methyl derivatives and the products of hydrogenation have the high storage density among the aromatic hydrocarbons (up to 7.3 wt%) which make it the extremely perspective as liquid hydrogen storage carriers. Therefore, the synthesis of the compounds with the higher added value (as decalin) is a highly important from scientific point of view. However, for the building up of "ideal" chemical system of hydrogen storage the development of effective catalytic systems with the composition and morphology adopted to the structure of aromatic substrate is highly needed. This review discusses the role of the metal in the catalytic hydrogenation of naphthalene and its derivatives for hydrogen storage. [Display omitted] • Chemical hydrogen storage in liquid organic hydrogen carriers is studied. • The supported metal role in the hydrogenation of naphthalene's is discussed. • The non-noble metal doped with small amounts of noble metal are promising catalysts. [ABSTRACT FROM AUTHOR]

Iron-based catalysts are gaining increased attention as promising and cost-effective materials for CO2 recycling. Their properties can be tuned by careful selection of the appropriate synthesis route, substrate, and catalytic system components. For the first time, a nanostructured material consisting of heterostructures of layered ferrihydrite (Fh) and hexagonal boron nitride (h-BN) nanoparticles has been obtained. Subsequent annealing ensures a uniform distribution of Fe nanoparticles (FeNPs) on the h-BN surfaces. Small Ag additions to the system lead to a significant decrease in the average size of FeNPs, presumably due to a seeding mechanism. Catalytic tests have shown that a low Ag content has a positive effect on the catalytic activity. Stability testing has demonstrated that the catalytic properties of the Fh/BN system improve over time, as does selectivity toward high-value-added hydrocarbons. Computational methods suggest a surface atomic configuration in which one Ag atom substitutes for one Fe atom in the (110) plane, resulting in better CO2 adsorption. [ABSTRACT FROM AUTHOR]

[Display omitted] The effect of the second metal (Pt, Pd, Ni and Fe) on the activity of copper phyllosilicate-based catalysts was investigated in the selective hydrogenation of dimethyl oxalate to ethylene glycol at 160–200 °C. The prepared catalysts were characterized by XRD, DRIFTS-CO and TEM methods. The conversion achieved over 10Fe/10Cu-PhySi catalyst was 68 % at 200 °C; at the same time, the full conversion with selectivity 98% was obtained at the temperature of 180 °C over a bimetallic 1Pt/Cu-PhySi catalyst. [ABSTRACT FROM AUTHOR]

BACKGROUND: The development of highly efficient and selective bimetallic catalytic systems for the hydrogenation of unsaturated compounds is an important scientific task. RESULTS: A new bimetallic 1%Cu‐1%Pt/SiO2 catalyst for the selective hydrogenation of phenylacetylene was developed. The bimetallic catalysts were prepared by a consecutive incipient wetness impregnation method and a redox method with preadsorbed hydrogen. We showed that the catalytic properties of 1%Cu‐1%Pt/SiO2 catalysts and selectivity toward styrene depend on the states of metals and interactions between Cu and Pt in bimetallic particles. The strong contact interaction between Pt0, Ptδ– and Cu<2+ in sample prepared by the impregnation method provides a high selectivity of about 82% in styrene formation, while the interaction between PtO and CuO phases provides a 60% selectivity under mild conditions. CONCLUSIONS: A new highly effective bimetallic Cu‐Pt/SiO2 catalyst was found for the selective hydrogenation of phenylacetylene with the formation of styrene. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Novel FeOx/Pd/SiO2 materials have been first synthesized by the redox methods including reduction with H2 at ambient conditions. The method of the temperature-programmed reduction with hydrogen (TPR-H2) was applied to study the influence of preparation conditions on the reducibility of supported FeOx species and stability of the reduced moieties to oxygen. The decreased temperature of β-PdH decomposition, as well as the intensive hydrogen consumption at − 50 to 100 °C due to FeOx reduction, has proved deposition of FeOx species on the surface of Pd nanoparticles. The phase composition, particle size and morphology were characterized with XRD, SEM and TEM. The highly reducible FeOx/Pd/SiO2 materials exhibited a multiple increase in the catalytic activity, as compared to the starting Pd/SiO2 material, in the selective hydrogenation of triple and double carbon bonds with molecular H2 in hydrogenation of phenylacetylene in liquid phase at room temperature and 1 bar hydrogen pressure. [ABSTRACT FROM AUTHOR]

In this study, novel SiO2- and Al2O3-supported Cu-Fe catalysts are developed for selective hydrogenation of 2-methyl-3-butyne-2-ol to 2-methyl-3-butene-2-ol under mild reaction conditions. TEM, XRD, and FTIR studies of adsorbed CO and TPR-H2 are performed to characterize the morphology, nanoparticle size, and particle distribution, as well as electronic state of deposited metals in the prepared catalysts. The deposition of Fe and Cu metal particles on the aluminum oxide carrier results in the formation of a mixed oxide phase with a strong interaction between the Fe and Cu precursors during the calcination. The highly dispersed nanoparticles of Fe2O3 and partially reduced CuOx, with an average size of 3.5 nm and with strong contact interactions between the metals in 5Cu-5Fe/Al2O3 catalysts, provide a high selectivity of 93% toward 2-methyl-3-butene-2-ol at complete conversion of the unsaturated alcohol. [ABSTRACT FROM AUTHOR]

The bimetallic Crn+/Pd0 nanoparticles have been synthesized for the first time by a two-step redox method. The method includes the deposition of Pd0 nanoparticles on the surface of SiO2 and TiO2 carriers followed by the deposition of Crn+ on the surface of Pd0 nanoparticles using the redox procedures, which are based on the catalytic reduction of Crn+ with H2 in aqueous suspensions at ambient conditions. Transmission (TEM) and scanning (SEM) electron microscopy, X-ray photoelectron spectroscopy (XPS), Fourie-transformed infrared spectroscopy of adsorbed CO (FTIR-CO), and CO chemisorption studies were performed to characterize the morphology, nanoparticle size, element, and particle distribution, as well as the electronic state of deposited metals in the obtained catalysts. A decrease in nanoparticle size from 22 nm (Pd/SiO2) to 2–6 nm (Pd/TiO2) makes possible deposition of up to 1.1 wt.% Cr most likely as Cr3+. The deposition of CrOx species on the surface of Pd nanoparticles was confirmed using FTIR of adsorbed CO and the method of temperature-programmed reduction with hydrogen (TPR-H2). The intensive hydrogen consumption in the temperature ranges from −50 °C to 40 °C (Cr/Pd/SiO2) and from −90 °C to −40 °C (Cr/Pd/TiO2) was first observed for the supported Pd catalysts. The decrease in the temperature of β-PdHx decomposition indicates the strong interaction between the deposited Crn+ species and Pd0 nanoparticle after reduction with H2 at 500 °C. The novel Crn+/Pd/TiO2 catalysts demonstrated a considerably higher activity in selective hydrogenation of phenylacetylene than the Pd/TiO2 catalyst at ambient conditions. [ABSTRACT FROM AUTHOR]