Complex Metallic Phases in Catalysis

Selective hydrogenation of acetylene on SiO2 supported Ni-In bimetallic catalysts: Promotional effect of In

“…The DFT calculations [21] have also demonstrated that the additives has lower activation energy for the ethylene desorption than for further hydrogenation, making the catalyst more selective. Again, the charge transfer from the additives to Pd can reduce the adsorption strength of acetylene and ethylene [6,11,12]. Therefore, the geometrical and electronic properties remarkably influence the catalyst performance for the selective hydrogenation of acetylene [12].…”

“…Again, the charge transfer from the additives to Pd can reduce the adsorption strength of acetylene and ethylene [6,11,12]. Therefore, the geometrical and electronic properties remarkably influence the catalyst performance for the selective hydrogenation of acetylene [12]. That is, both geometrical and electronic effects due to In suppress the formation of strong multi-σ-adsorbed ethylene and facilitate the desorption of ethylene from the Ni x In/SiO 2 catalysts, confirmed by the C 2 H 4 -TPD profiles (Fig.6).…”

“…To improve the performance of mono-metallic Pd catalyst, a second metal (such as Ag [6], Zn [7], Cu [8], Au [9,10] and Ga [11,12]) is added to form alloy or intermetallic compound. In the alloy (such as Pd-Ag [6]) and intermetallic compound (such as PdGa [11,12]), the second metal atoms can dilute the surface Pd ones and subsequently to form more isolated Pd atoms, while the isolated Pd atoms can restrain the adsorption of acetylene or ethylene via triply-bond that can easily be hydrogenated to ethane.…”

Structure of the monoclinicAl13Fe4(010)complex metallic alloy surface determined by low-energy electron diffraction

“…These so-called quasicrystal approximants are helpful in analyzing the structures of quasicrystals because they allow the use of traditional structure determination methods and can provide a starting model for the quasicrystal structure determination [1][2][3]. Some CMAs have also been found to offer a low-cost alternative for the design of selective and stable catalysts in heterogeneous catalysis [4]. The idea behind this site isolation concept is that small well-separated sites that contain an active transition-metal (TM) element reduce the number of possible reaction products by limiting the number of possible adsorption geometries.…”

“…In this paper, we present a structural investigation of the surface of this compound by quantitative low-energy electron diffraction under ultra-high-vacuum conditions. Monoclinic Al 13 Fe 4 , which belongs to the space group C2/m (mC102), is a four-layer approximant to the decagonal quasicrystal surface. Its structure is usually given as a stacking of pseudotenfold (p − 10f ) flat (F ) and puckered (P ) layers in a F 1 P 1 F 2 P 2 sequence in the [010] direction.…”