scholarly journals Catalysis-tunable Heusler alloys in selective hydrogenation of alkynes: A new potential for old materials

2018 ◽  
Vol 4 (10) ◽  
pp. eaat6063 ◽  
Author(s):  
Takayuki Kojima ◽  
Satoshi Kameoka ◽  
Shinpei Fujii ◽  
Shigenori Ueda ◽  
An-Pang Tsai
Keyword(s):  
Intermetallic Compound ◽  
Selective Hydrogenation ◽  
Reaction Rate ◽  
Catalytic Properties ◽  
Heusler Alloys ◽  
Fine Tuning ◽  
Elemental Substitution ◽  
Ensemble Effects ◽  
Compound Materials

Heusler alloys (X2YZ) are well-established intermetallic compound materials in various fields because their function can be precisely adjusted by elemental substitution (e.g., X2YZ1−xZ′x). Although intermetallic compound catalysts started attracting attention recently, catalysis researchers are not familiar with Heusler alloys. We report their potential as novel catalysts focusing on the selective hydrogenation of alkynes. We found that Co2MnGe and Co2FeGe alloys have great alkene selectivity. Mutual substitution of Mn and Fe (Co2MnxFe1−xGe) enhanced the reaction rate without changing selectivity. The substitution of Ga for Ge decreased the selectivity but increased the reaction rate monotonically with Ga composition. Elucidation of these mechanisms revealed that the fine tuning of catalytic properties is possible in Heusler alloys by separately using ligand and ensemble effects of elemental substitution.

Direct observation of Fe-Al-Zn ternary intermetallic compound and its transformation during the early stage of hot-dip galvanizing

1993 ◽  
Vol 51 ◽  
pp. 1116-1117
Author(s):  
C. S. Lin ◽  
W. A. Chiou ◽  
M. Meshii
Keyword(s):  
Intermetallic Compound ◽  
Reaction Rate ◽  
Diffusion Rate ◽  
Early Stage ◽  
Zinc Bath ◽  
Steel Sheets ◽  
Direct Observations ◽  
Solid Iron ◽  
Iron And Zinc ◽  
Ternary Intermetallic Compound

The galvannealed steel sheets have received ever increased attention because of their excellent post-painting corrosion resistance and good weldability. However, its powdering and flaking tendency during press forming processes strongly impairs its performance. In order to optimize the properties of galvanneal coatings, it is critical to control the reaction rate between solid iron and molten zinc.In commercial galvannealing line, aluminum is added to zinc bath to retard the diffusion rate between iron and zinc by the formation of a thin layer of Al intermetallic compound on the surface of steel at initial hot-dip galvanizing. However, the form of this compound and its transformation are still speculated. In this paper, we report the direct observations of this compound and its transformation.The specimens were prepared in a hot-dip simulator in which the steel was galvanized in the zinc bath containing 0.14 wt% of Al at a temperature of 480 °C for 5 seconds and was quenched by liquid nitrogen.

scholarly journals Comparing hydrogen absorption kinetics of the samples of intermetallic compound and metal hydride compact on its basis

2021 ◽  
Vol 2057 (1) ◽  
pp. 012043
Author(s):  
I A Romanov ◽  
V I Borzenko ◽  
A N Kazakov
Keyword(s):  
Intermetallic Compound ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Reaction Rate ◽  
Nickel Foam ◽  
High Confidence ◽  
Compact Sample ◽  
Kinetics Of ◽  
Rate Controlling Step ◽  
Absorption Of Hydrogen

Abstract This work is devoted to an experimental study and comparison of the kinetics of hydrogen absorption by an intermetallic compound LaNi4.4Al0.3Fe0.3 in form of pure intermetallic compound free backfill and a compact based on it obtained by cold pressing with a spiral matrix of nickel-foam. To calculate the kinetic parameters of the hydrogen absorption reaction, the initial rates method is used. The PCT absorption isotherms are measured at temperatures of 313, 333, and 353 K. The experimental data are described with quite high confidence by the chosen model, which assumes that the reaction rate controlling step is the dissociative absorption of hydrogen on the surface of the a-phase. The rate of hydrogen absorption increases with increasing pressure drop and temperature. It is shown that the rate of hydrogen absorption by the sample of pure IMC is significantly less dependent on temperature compared to the compact sample. In addition, the reaction rate at temperatures of 313 and 333 K is higher for the free backfill sample, and at 353 K it is higher for the metal hydride compact. The values of the absorption constant and the activation energy of the hydrogen absorption reaction are determined for both samples.

Reaction rate of combustion synthesis of an intermetallic compound

1998 ◽  
Vol 95 (2) ◽  
pp. 175-181 ◽  
Author(s):  
Tomohiro Akiyama ◽  
Hiromichi Isogai ◽  
Jun-ichiro Yagi
Keyword(s):  
Intermetallic Compound ◽  
Combustion Synthesis ◽  
Reaction Rate ◽  
Rate Of Combustion

The selective hydrogenation of furfural over intermetallic compounds with outstanding catalytic performance

2019 ◽  
Vol 21 (19) ◽  
pp. 5352-5362 ◽  
Author(s):  
Yusen Yang ◽  
Lifang Chen ◽  
Yudi Chen ◽  
Wei Liu ◽  
Haisong Feng ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Selective Hydrogenation ◽  
Furfuryl Alcohol ◽  
Catalytic Performance ◽  
Hydrogenation Selectivity

An intermetallic compound (Ni3Sn2) was prepared from a hydrotalcite precursor, which exhibited outstanding hydrogenation selectivity from furfural to furfuryl alcohol.

scholarly journals Surface and Catalytic Properties of NiO–Fe2O3 Solids Supported on Al2O3

1996 ◽  
Vol 13 (5) ◽  
pp. 409-421 ◽  
Author(s):  
G.A. El-Shobaky ◽  
A.M. Ghozza ◽  
N.M. Deraz
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Catalytic Properties ◽  
Unit Area ◽  
Surface Characteristics ◽  
Reaction Rate Constant ◽  
Oxidation Of Co ◽  
Catalytic Activities ◽  
Surface Areas ◽  
Specific Surface Areas

A series of NiO–Fe2O3 catalysts supported on γ-Al2O3 was prepared. The effect of the NiO and Fe2O3 contents and the precalcination temperature on the surface and catalytic properties of the various solids has been investigated. The surface characteristics, viz. SBET, Vp and r, were determined using N2 adsorption conducted at –196°C. The catalytic activities of the various solids were studied using the oxidation of CO by O2 at temperatures in the range between 150°C and 400°C. The prepared solids were preheated in air at various temperatures between 400°C and 1000°C. The results obtained revealed that the SBET values of the different solids decrease progressively on increasing the precalcination temperature above 400°C due to sintering. The specific surface areas were also found to decrease on increasing both the NiO and Fe2O3 contents. The catalytic activities, expressed as reaction rate constant (k) and reaction rate constant per unit area (k), were found to decrease on increasing the precalcination temperature in the range 400–1000°C. Furthermore, the amounts of NiO and Fe2O3 in the different solids modified their catalytic activities in different manners.

Synthesis of Co–Sn intermetallic nanocatalysts toward selective hydrogenation of citral

2016 ◽  
Vol 4 (33) ◽  
pp. 12825-12832 ◽  
Author(s):  
Junyao Zhou ◽  
Yusen Yang ◽  
Changming Li ◽  
Shitong Zhang ◽  
Yudi Chen ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Selective Hydrogenation ◽  
Catalytic Performance

Three Co–Sn intermetallic compound catalysts are prepared via a hydrotalcite approach, which show satisfactory catalytic performance toward selective hydrogenation of citral.

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