Nickel–Aluminum Intermetallic Compounds as Highly Selective and Stable Catalysts for the Hydrogenation of Naphthalene to Tetralin

Abstract

Selective hydrogenation of naphthalene to tetralin was conducted by using Ni–Al intermetallic compounds (IMCs) prepared by a chemical synthetic route. Ni–Al IMC catalysts achieved a lasting high conversion with 100 % selectivity up to 125 h. During the synthesis process, the Ni–Al IMCs underwent the following phase transformation as a function of the content of the Al source (LiAlH4): Ni(cubic)→Ni3Al(tetragonal)→NiAl(cubic)→Ni2Al3(hexagonal). In the selective hydrogenation of naphthalene, the catalytic activity of NiAl was much higher than that of metallic Ni and other Ni–Al IMCs (Ni3Al and Ni2Al3). The results can be understood by a combination of site isolation and alteration of the electronic structure by chemical bonding. Ni atoms are scattered and spatially isolated by Al atoms, which in turn resists carbon deposition. The findings provide a useful approach to tailor the catalytic properties of transition metals by formation of IMCs, which could be applicable in heterogeneous catalysis.

Room‐Temperature Morphology‐Controlled Synthesis of Nickel and Catalytic Properties of Corresponding Ru/Ni Catalysts

“…In the Ni 2p XPS spectra (Figure a–c), the satellite peaks with higher binding energy (861.2 eV and 879.7 eV) can be attributed to multi‐electron excitation . Through analyzing and fitting Ni 2p XPS peaks of these three Ru/Ni samples, we can clearly find that the nickel specie on their surface is mainly oxidation state nickel, such as NiO (binding energy (B.E)=853.9 eV and 871.2 eV), Ni(OH) 2 (B.E=855.4 eV and 872.9 eV) and NiOOH (B.E=857.1 eV and 874.4 eV) . But the specie ratio of nickel(0)/(nickel oxide+nickel hydroxide+nickel oxyhydroxide) on the surface of Ru/Ni‐No is obviously higher than that of Ru/Ni‐CTAB or Ru/Ni‐PVP.…”

“…[32] Through analyzing and fitting Ni 2p XPS peaks of these three Ru/Ni samples, we can clearly find that the nickel specie on their surface is mainly oxidation state nickel, such as NiO (binding energy (B.E) = 853.9 eV and 871.2 eV), Ni(OH) 2 (B.E = 855.4 eV and 872.9 eV) and NiOOH (B.E = 857.1 eV and 874.4 eV). [33][34][35][36][37][38] But the specie ratio of nickel(0)/(nickel oxide + nickel hydroxide + nickel oxyhydroxide) on the surface of Ru/Ni-No is obviously higher than that of Ru/Ni-CTAB or Ru/Ni-PVP. This is probably because the size of Ru/Ni-No is tinier than that of Ru/Ni-CTAB or Ru/Ni-PVP, resulting in being easily oxidized in air.…”

Magnetically separable mesoporous silica‐supported palladium nanoparticle‐catalyzed selective hydrogenation of naphthalene to tetralin

“…Converting this chemical into useful products is meaningful from both environmental and industrial viewpoints . In this regard, partial hydrogenation is a practical method to consume naphthalene because the product tetralin generated following this reaction is a useful industrial intermediate that is comprehensively used as a solvent in industrial production, as an intermediate in agricultural chemical synthesis, and as a good hydrogen donor in fuel cells . ] In industrial catalysis, a variety of metal catalysts, such as Pd, Pt, [ Rh, Ru, Ir, and Ni, have been developed for the hydrogenation/dehydrogenation reactions, with alumina, zeolite, or activated carbon usually employed as the catalyst support .…”

ENHANCED CATALYTIC ACTIVITY ON THE NAPHTALENE HYDROGENATION REACTION OVER Pt-Pd/Al2O3-CeO2 CATALYSTS

“…For fuels quality parameters, such as cetane number, paraffins are the most desirable components, while the unfavorable components are multi-ring aromatic compounds due to environmental regulations. The catalytic hydrogenation reactions have been therefore the focus of many recent studies due to the interest for deep hydrogenation (HYD) of aromatics (Chen et al, 2015;Ju et al, 2015;Téllez-Romero et al, 2015;Escobar et al, 2017;Sánchez-Minero et al, 2010;and Liu et al, 2016). In particular, the hydrogenation of naphthalenes produces tetralins while the complete saturation leads to the formation of decalins.…”

“…In particular, the hydrogenation of naphthalenes produces tetralins while the complete saturation leads to the formation of decalins. Moreover, this reaction is also of industrial interest, not only due to its role in upgrading coal liquids and diesel fuels, but also because of the production of solvents, such as tetralin (Chen et al, 2015). Some other types of catalysts have been tried, with the aim of increasing the electron defficiency of noble metals via interaction with an acidic support or introducing a secondary metal (Ju et al, 2015).…”