scholarly journals Enhancing catalytic properties of ligand-protected gold-based 25-metal atom nanoclusters by silver doping

2022 ◽  
Vol 518 ◽  
pp. 112095
Author(s):  
Ricca Rahman Nasaruddin ◽  
Max J. Hülsey ◽  
Jianping Xie
Keyword(s):  
Metal Atom ◽  
Catalytic Properties ◽  
Silver Doping

The Comparison of Different Preparation Methods of Catalysts for Furfural Hydrogenization to 2 - Methyl Furan

2013 ◽  
Vol 791-793 ◽  
pp. 68-71
Author(s):  
Zeng Xin Li ◽  
Tong Zhu Han ◽  
Wen Xia Guo ◽  
Guo Ming Wang
Keyword(s):  
Metal Atom ◽  
Metal Particle ◽  
Catalytic Properties ◽  
Hydrogenation Reaction ◽  
Impregnation Method ◽  
Preparation Methods ◽  
Metal Particle Size ◽  
Furfural Hydrogenation ◽  
Distribution Uniformity ◽  
Xrd Patterns

Three different kinds of preparation methods were contrasted and studied to furfural hydrogenation catalyst for 2 - methyl furan production.Cu, Cr-based catalysts are prepared by three different methods, and the differences were also studied in the structure of these catalysts and their catalytic properties on furfural hydrogenation reaction. From the XRD patterns of samples prepared by different methods of Cu-Cr/γ-Al2O3, The results show that: the metal particle size is:the ordinary impregnation method > coprecipitation > solvated metal atom impregnation method. From the SEM photographs by samples, distribution uniformity of the catalyst ion surface: ordinary impregnation method > coprecipitation > solvated metal atom impregnation method. The reduction degree of the metal: solvated metal atom impregnation ordinary impregnation coprecipitation method. Furfural hydrogenation experimental results show that the order of catalytic activity is solvated metal atom > general impregnation coprecipitation; the selectivity order of 2 - methyl furan: coprecipitation> ordinary impregnation method solvated metal atom impregnation method.

Activation of Alkanes by Transition Metal Nitrides and Carbides

1998 ◽  
Vol 549 ◽  
Author(s):  
C. A. Bennett ◽  
M. K. Neylon ◽  
H. H. Kwon ◽  
S. Choi ◽  
K. E. Curry ◽  
...  
Keyword(s):  
Metal Atom ◽  
Catalytic Properties ◽  
Lattice Structure ◽  
Reaction Rates ◽  
Transition Metal Nitrides ◽  
Atom Type ◽  
Group Vi ◽  
Group V ◽  
Dehydrogenation Reactions ◽  
Temperature Programmed Reaction

AbstractGroup V and VI nitrides and carbides were synthesized by the temperature programmed reaction of metal oxides with ammonia or an equimolar mixture of methane/hydrogen. The synthesis protocols were developed using thermogravimetric techniques. The resulting nitrides and carbides were primarily mesoporous and possessed surface areas in the range of 11 – 81 m2/g. Their alkane activation rates were comparable to a Pt-Sn/AL20 3 dehydrogenation catalyst and the surface area normalized reaction rates decreased in the following order: Mo2N > W2C > WC > W2N > WC1−x > VCoa0.05N > MO2C > VN = VC > NbMo0.01 N > NbMo0.05 > NbN = NbC. The activities measured at 450°C ranged between 1011 – 1013 molecules/cm2/s for n-butane and 1012 – 1013 molecules/cm2/s for n-hexane. The Group VI nitrides and carbides were far more active than the Group V materials. The Group VI materials catalyzed the hydrogenolysis and dehydrogenation reactions with similar activities whereas the Group V materials were more than 98% selective to dehydrogenation. While the metal atom type had the most significant effect on the catalytic properties, the lattice structure of the material also played a role. In particular, we observed that WC (hex) was almost twice as active as WC1-x (fcc). Nitrides and carbides of the same metal and lattice structure possessed similar catalytic properties, implying that the effect of the non-metal atom type was minimal. The W2N catalyst was found to be highly selective towards n-butane isomerization. The multimetallic nitrides each demonstrated some form of synergy.

Guiding the Catalytic Properties of Copper for Electrochemical CO2 Reduction by Metal Atom Decoration

2021 ◽  
Author(s):  
Yusaku F. Nishimura ◽  
Hong-Jie Peng ◽  
Stephanie Nitopi ◽  
Michal Bajdich ◽  
Lei Wang ◽  
...  
Keyword(s):  
Metal Atom ◽  
Catalytic Properties ◽  
Co2 Reduction ◽  
Electrochemical Co2 Reduction

Microstructure and reactivity of small metal particles: The role of Ce additives

1992 ◽  
Vol 50 (1) ◽  
pp. 318-319
Author(s):  
L.D. Schmidt ◽  
K. R. Krause ◽  
J. M. Schwartz ◽  
X. Chu
Keyword(s):  
Atmospheric Pressure ◽  
Noble Metals ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Chemical Shifts ◽  
Catalytic Converter ◽  
Structural Evolution ◽  
Single Particles ◽  
Small Metal Particles

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

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