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The metallic glass Gd_52.5Co_18.5Al₂₈Zr₁ preserves the amorphous structure after hydrogenation at 473 K for 48 h. The absorption of hydrogen leads to the reduction of the magnetic transition temperature due to the expansion of the interatomic distance. The magnetic anisotropy is introduced and the coercivity and remanence are 352 Oe and 12.5 emu/g at 1.8 K, respectively. The maxima of magnetic entropy changes are 11.3 and 7.5 J/kg K with the magnetic field changes of 0 to 70 kOe and 0 to 50 kOe, respectively. The decline of the magnetic entropy changes can be attributed to the disappearance of the collinear ferromagnetic characteristics and the difficulty of saturation for the magnetization after hydrogenation.

By performing density functional theory (DFT) calculations, we demonstrate that periodically repeating heterostructures of zigzag borophene nanoribbons (BNR) of different widths can form stable borophene superlattice (BSL). The energy band structures of BSL can be modulated through modifying the width and length of the segments. A metal-semiconductor transition can be obtained when the length of each segment is lengthened, whereas, the magnetism of BSL is influenced by the width of the segments. In those magnetic systems, the magnetic moments are mainly localized on protruding B atoms located at the edge, while no magnetic moments occur in the center B atoms. The hydrogenated BNR and BSL are further investigated. The hydrogenation can modify the electronic properties of BNR and BSL as well as quench the magnetism. All hydrogenated BNR and BSL are non-magnetic. Our results indicate that great potential exists in these systems for borophene utilization in nanoelectronics and spintronics.

The hydrogenation activity and sulfur-tolerant ability of nano-NiMo catalysts prepared by sol–gel method were investigated by hydrogenation of ethylbenzene containing thiophene. The results show that the adding of molybdenum has a profound effect on the structure and the sulfur-tolerant ability of nickel-based catalyst. The catalyst with MoNi ratio of 0.16 showed maximum hydrogenation activity and good sulfur resistance when compared to other catalysts. It seems that new hydrogen-adsorbed phase is formed at high temperature and the quantity of hydrogen adsorbed increases greatly when Mo is added to the nickel-based catalysts.

We report DFT calculations on potential intramolecular, enantioselective hydrogenation catalysts based around borenium-carbenes based on a camphor scaffold. Using the M06-2X meta-hybrid functional, we find frustrated Lewis pair (FLP) behavior with suitably chosen linkers that prevent association of Lewis bases with the borenium center. These intramolecular FLPs are predicted to be able to heterolytically dissociate H₂. Barriers to dissociation and the endo/exoergic nature of the reaction can be tuned by the nature of the base and substituent on B. The reactivity of the hydrogenated FLP catalyst with olefin and carbonyl substrates is then explored: we predict concerted reactions for all substrates considered with relatively low barriers and large exoergic character. Hydrogenation of both faces of a prochiral substrate is also examined, indicating a small but significant variation in reaction barrier in favor of the Si-face, ascribed to stronger interactions with the aromatic $\pi$-system in the TS compared to the Re-face.

The synthesis of porphyrins conjugated with sugar moieties is described. meso-Aminophenyl-substituted and β-amino-substituted porphyrin derivatives reacted with benzyl protected glucuronic acid leading to gluco-conjugated hybrids, which after reductive deprotection of OH groups (H₂, 10% Pd/C) gave the desired target products of increased hydrophilicity. Alternatively, this type of similar conjugates were obtained through S_NAr reaction of meso-tetrakis(pentafluorophenyl)porphyrin with aminomethyl sacharides. The substitution took place selectively in para-position of meso-perfluorophenyl rings, thus giving rise to one, two, or three times substituted products carrying N-linked glucoside residues.

The Pd–P selective catalyst for liquid-phase hydrogenation of o-chloronitrobenzene (o-CNB) was obtained by the reduction of Pd(acac)₂ with hydrogen at 80^∘C in the presence of white phosphorus (P/Pd = 1) in N,N-dimethylformamide (DMF). It has been shown [(high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD)] that such low-temperature synthesis of the Pd–P catalyst affords nanoparticles of palladium phosphides (Pd₅P₂, PdP₂), the Pd₅P₂ phosphide being prevailing. On the nanoparticle surface, palladium is present as a phosphide (BE (Pd3d_5∕2) = 336.2 eV; BE (P2p_3∕2) = 130 eV) and as palladium clusters of ≈ 1 nm in diameter. The formation of the Pd–P catalyst proceeds through a number of stages: a redox process between Pd(acac)₂ and white phosphorus affording mainly PdP₂ nanoparticles, H₃PO₃ and acacH; next follows the reduction of unreacted Pd(acac)₂ with hydrogen at 80^∘C and the reaction of Pd(0) atoms with each other and with PdP₂. It is assumed that formation of small palladium clusters on the surface of the Pd₅P₂ nanoparticles ensures the high selectivity of the Pd–P catalyst in the o-CNB hydrogenation.

A simple route to fabricate nano-composite oxides CuO-Cr₂O₃ using hexadecyltrimethylammonium bromide (CTAB)-templated Cu-Cr hydrotalcite as the precursor is presented. This novel method is based on CTAB-templating effect for mesostructure directing and using the cheap metal nitrate, followed by removal of CTAB. It was indicated that the nano-composite CuO-Cr₂O₃ was formed during the removal of CTAB. X-ray diffraction (XRD) and transitional electronic microscopy (TEM) revealed nice nano-composite oxides CuO-Cr₂O₃ were formed with high crystallinity. N₂ adsorption and desorption indicated that a high surface area of 170.5 m²/g with a pore size of 2.7 nm of the nano-composite CuO-Cr₂O₃ was facilely resulted. The as-synthesized nano-composite oxides CuO-Cr₂O₃ display good catalytic activities for hydrogenation of furfural to furfuryl alcohol, whereas 86% selectivity was achieved at 75% conversion of furfural.

Hydrogenated amorphous silicon nitride is useful as an anti-reflection coating on solar cells. The addition of hydrogen atoms to amorphous silicon nitride can reduce the dangling bonds that exist on the surface. The objective of this paper is to clarify on the behavior of hydrogen atoms absorbed in silicon nitride during the hydrogenation process at various temperatures. We investigate, in particular, the silicon and hydrogen bonds that are formed by the transfer of electrons from hydrogen to silicon to form ${\text{Si}}^{1-}$, ${\text{Si}}^{2-}$, ${\text{Si}}^{3-}$, and ${\text{Si}}^{4-}$ ions. The conversion of ${\text{Si}}^{1-}$ ions into ${\text{Si}}^{2-}$ ions and then also into ${\text{Si}}^{3-}$ and ${\text{Si}}^{4-}$ occurs during enhancement of the hydrogen atoms absorbed. Hydrogenated amorphous silicon nitride was stabilized through the passivation of dangling bonds of silicon atoms and nitrogen atoms by the absorbed hydrogen atoms. The passivation was indicated by enhancement of over-coordinated silicon and nitrogen atoms as well as the reduction of under-coordinated silicon and nitrogen atoms. It was found that the thermal energy from high hydrogenation temperature was primarily used by hydrogen atoms to diffuse more and to penetrate deeper into silicon nitride rather than being used for the ionization of silicon atoms. Finally, we stress that these reactive molecular dynamic simulations have led to substantial progress in understanding how hydrogen atoms interact with amorphous silicon nitride during hydrogenation.

Various carbon nanostructures, including graphene, are very promising for application in hydrogen storage. One of the promising ways to increase the hydrogen storage capacity of graphene is crumpling. In this work, an increase of hydrogen binding energy to graphene with ripple is studied by first-principle calculations. It is shown that binding energy can be considerably increased for hydrogen atom attached outside the cavity of graphene ripple. Further, by molecular dynamics simulation, it is shown that physisorption of hydrogen in the cavities of crumpled graphene is also very promising if hydrostatic compression is applied to the structure. The volumetric density of hydrogen storage can be increased for 14% for the compressed crumpled graphene in comparison with undeformed structure. Results obtained by two simulation techniques showed that crumpled graphene can be considered as a very promising media for hydrogen storage both by chemisorption and physisorption.

Hydroprocessing is a conventional operation in the petroleum refinery. Recent developments in biofeedstock-derived fuels and stringent environmental legislation brought up new challenges in this traditional area. This chapter reviews hydroprocessing reactions including hydrodesulfurization, hydrodenitrogenation, hydrodeoxygenation, hydrogenation, hydrocracking, and hydrodemetallization, reactivity and reaction pathways of typical chemicals resulted from biofeedstock and petroleum, surface chemistry of hydroprocessing catalysts, and hydroprocessing catalyst models.

In the atmosphere carbon dioxide (also called carbonic anhydride: CO₂) is the most abundant form of carbon (Section 4.1). In the lithosphere and hydrosphere carbon is found in the form of carbonates ${(\text{CO}}_3^{2-})$ and bicarbonates (hydrogen carbonates: ${\text{HCO}}_3^{-})$, bound to mono-cations such as sodium Na⁺, potassium, K⁺, ammonium cation, ${\text{NH}}_4^{+}$, or dications such as calcium Ca²⁺ and magnesium Mg²⁺. Carbon dioxide, carbonates and bicarbonates are mineral carbon compounds (Sections 4.3, 4.5 and 4.6). These compounds are described, their uses and their most important properties are presented. This exercise will allow us to introduce fundamental notions about chemical equilibria (Section 4.2).

This book chapter is dedicated to the synthesis and application of manganese carbonyl alkyl complexes. At first, an overview of the synthesis of such complexes is given. Furthermore, selected stochiometric reactions of manganese carbonyl alkyl complexes with various ligands, including the renowned carbonylation reaction to give carbonyl acyl species, are discussed. Apart from stochiometric transformations, modern applications in catalysis are elucidated. These applications cover the hydrogenation reactions of (polarized) carbon–carbon and carbon–heteroatom multiple bonds. In addition to that, the potential of manganese carbonyl alkyl complexes in the fields of hydrofunctionalization and cross-coupling chemistry is presented.

Plastics have become one of the most integral parts of our day-to-day lives; however, after use, plastic waste accumulates on land and in water bodies, which wreaks havoc in the environment by releasing toxic gases. As the usage of plastic increases, it will result in the depletion of natural resources and greater difficulties in managing plastic waste. Accordingly, in this chapter, we focus on various types of resources, such as fuel, gas, energy, and electricity, which are recovered from plastic waste through different waste management technologies such as primary, secondary, tertiary, and quaternary recycling. This chapter is set forth by critically evaluating different types of plastic waste technologies, the products, and their byproducts formed during tertiary treatment. Material and resource recovery of different types of waste plastics through gasification and pyrolysis offers significant environmental benefits by promoting resource extraction and reducing the associated environmental impacts linked to the extraction process.

Vapor phase hydrogen transfer reaction between acrolein and isopropanol has been investigated using a Ag₂O-B₂O₃-MgO catalyst in a conventional fixed bed flow system at atmospheric pressure. A high selectivity (95.4%) of allyl alcohol was obtained with 100% of conversion at 270°C, isopropanol/Acrolein volume ratio = 15, contact time = 57.6 g-cat hr/mol. Under this condition, both activity and selectivity of Ag₂O-B₂O₃-MgO catalyst were sperior to that of the B₂O₃-MgO catalyst. The former catalyst had a long-lived activity more than the latter catalyst.

The influence of reaction conditions on the composition and yield of biodiesel made by hydrotreating of waste cooking oil were investigated with Ni-Mo-W/Al₂O₃ catalyst. The results demonstrated that the saturated C₁₅-C₁₈ paraffins was the main product from the hydrotreating of waste cooking oil. With the increase in reaction temperature and LHSV, or the decrease of pressure and hydrogen/oil volume ratio, the decarboxylation or decarbonylation was enhanced. Otherwise, it would be advantageous to deoxidation reaction. The product yield from the hydrotreating of waste cooking oil increased when the reaction temperature and LHSV decreased and when reaction pressure and hydrogen/oil volume ratio increased.

The influences of reaction conditions on the composition and yield of biodiesel made by hydrotreating of rubber seed oil were investigated using Ni-Mo-W/Al₂O₃ catalyst. The results demonstrated that the saturated C₁₅-C₁₈ paraffins were the main product from the hydrotreating of rubber seed oil. Increases in reaction temperature and LHSV or the decrease of pressure and hydrogen/oil volume ratio promotes the enhancement of decarboxylation or decarbonylation, which decreases the yield of the product from the hydrotreating of rubber seed oil. The yield of product from the hydrotreating of rubber seed oil increased when the reaction temperature and LHSV decreased or reaction pressure and hydrogen/oil volume ratio increased.