scholarly journals Catalytic Activity of Highly Dispersed Palladium. II. X-Ray Photoelectron Spectroscopic and Thermal Desorption Studies of the Effects of ZrO2Added to α-Alumina-supported Palladium

1981 ◽  
Vol 54 (12) ◽  
pp. 3711-3716 ◽  
Author(s):  
Bu Yong Lee ◽  
Yasunobu Inoue ◽  
Iwao Yasumori
Keyword(s):  
Catalytic Activity ◽  
Thermal Desorption ◽  
X Ray ◽  
Highly Dispersed ◽  
Supported Palladium

scholarly journals Pt/CeO2 with residual chloride as reusable soft Lewis acid catalysts: application to highly efficient isomerization of allylic esters

2021 ◽  
Author(s):  
Qi-An Huang ◽  
Asahi Haruta ◽  
Yuhya Kumamoto ◽  
Haruno Murayama ◽  
Eiji Yamamoto ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Lewis Acid ◽  
High Catalytic Activity ◽  
Acid Catalysts ◽  
Lewis Acid Catalysts ◽  
X Ray ◽  
Solvent Free Conditions ◽  
Highly Dispersed ◽  
Silica Alumina ◽  
Allylic Esters

Abstract Heterogeneous acid and base catalysts play a crucial role in many important chemical processes. Hard Lewis and Brønsted acid catalysts like silica-alumina and zeolites have been widely applied in numerous reactions; however, developing reusable and active soft Lewis acid catalysts remain a challenge. Herein, we demonstrate for the first time that a highly dispersed supported platinum catalyst can act as a heterogeneous soft Lewis acid. High turnover numbers and reusability were observed in the isomerization of allylic esters under solvent-free conditions. Moreover, the as-prepared catalysts are characterized by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) analyses, revealing that the highly dispersed Pt clusters with Pt–Cl bonds play a key role in the high activity. The residual chloride anion enhances the Lewis acidity of the Pt metal center and thus improves the catalytic activity. Simultaneously, the high catalytic activity of Pt/CeO2 with residual chloride and the soft Lewis acid mechanism are also proved by density functional theory (DFT) calculations based on the model reaction.

Formation of Highly Dispersed Rhodium Particles by Chemical and Photochemical Reduction

1992 ◽  
Vol 272 ◽  
Author(s):  
Zhibang Duan ◽  
M.J. Hampden-Smith ◽  
A. Datye ◽  
P.J. Nigrey ◽  
C. Quintana ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Metal Particles ◽  
X Ray Diffraction ◽  
Photochemical Reduction ◽  
X Ray ◽  
Homogeneous Solutions ◽  
Highly Dispersed ◽  
Metal Organic

ABSTRACTNanometer-sized metal particles have been prepared by chemical and photochemical reduction of homogeneous solutions of metal-organic rhodium(I) compounds. Reduction of [(COD)RhCl]2 with LiBEt3H in THF resulted in the formation of solutions containing crystalline, mono-dispersed Rh particles with average sizes of 2–4nm as determined by TEM and SAXS. The species [(COD)RhH]4 was isolated during the formation of the Rh colloids but was found not to be an intermediate in the reduction of Rh(I) to Rh(0). The catalytic activity of these highly dispersed metals towards pyrene hydrogenation has been investigated. Photochemical reduction of [(ethylene)2Rh(OEt)]2 at room temperature also resulted in formation of Rh as shown by TEM, EDS, ED and X-ray diffraction.

Biopreparation of Highly Dispersed Pd Nanoparticles on Bacterial Cell and Their Catalytic Activity for Polymer Electrolyte Fuel Cell

2010 ◽  
Vol 1272 ◽  
Author(s):  
Takashi Ogi ◽  
Ryuichi Honda ◽  
Koshiro Tamaoki ◽  
Norizo Saito ◽  
Yasuhiro Konishi
Keyword(s):  
Catalytic Activity ◽  
Fuel Cell ◽  
Palladium Catalyst ◽  
Bacterial Cell ◽  
Metal Ion ◽  
Room Temperature ◽  
Rapid Development ◽  
Polymer Electrolyte Fuel Cell ◽  
Highly Dispersed ◽  
Supported Palladium

AbstractRapid development in the area of low-temperature fuel cells has led to increased attention on catalyst synthesis with cost effective and environmentally-benign technology (green chemistry). In this study, a highly dispersed palladium nanoparticle catalyst was successfully prepared on a bacterial cell support by a single-step, room-temperature microbial method without dispersing agents. The metal ion reducing bacterium Shewanella oneidensis were able to reduce palladium ions into insoluble palladium at room temperature when formate was provided as the electron donor. The prepared biomass-supported palladium nanoparticles were characterized for their catalytic activity as anodes in polymer electric membrane fuel cell for power production. The maximum power generation of the biomass-supported palladium catalyst was up to 90% of that of a commercial palladium catalyst.

Bis(μ-carboxylato)dienerhodium(I) Complexes - Synthesis, Characterization and Catalytic Activity

2008 ◽  
Vol 73 (8-9) ◽  
pp. 1205-1221 ◽  
Author(s):  
Jiří Zedník ◽  
Jan Sedláček ◽  
Jan Svoboda ◽  
Jiří Vohlídal ◽  
Dmitrij Bondarev ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Diffraction Analysis ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray

Dinuclear rhodium(I) η2:η2-cycloocta-1,5-diene (series a) and η2:η2-norborna-2,5-diene (series b) complexes with μ-RCOO- ligands, where R is linear C21H43 (complexes 1a, 1b), CH2CMe3 (2a, 2b), 1-adamantyl (3a, 3b) and benzyl (4a, 4b), have been prepared and characterized by spectroscopic methods. Structures of complexes 2b, 3a and 4a were determined by X-ray diffraction analysis. Complexes prepared show low to moderate catalytic activity in polymerization of phenylacetylene in THF giving high-cis-transoid polymers, but they show only oligomerization activity in dichloromethane.

Synthesis, structural characterization and catalytic activity of chlororuthenium(II) complexes with substituted Schiff base/phosphine ancillary ligands

2020 ◽  
Vol 75 (9-10) ◽  
pp. 851-857
Author(s):  
Chong Chen ◽  
Fule Wu ◽  
Jiao Ji ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Schiff Base ◽  
Catalytic Activity ◽  
Structural Characterization ◽  
Room Temperature ◽  
Molecular Structures ◽  
Cationic Complex ◽  
Neutral Complex ◽  
Ancillary Ligands ◽  
X Ray ◽  
X Ray Crystallography

AbstractTreatment of [(η6-p-cymene)RuCl2]2 with one equivalent of chlorodiphenylphosphine in tetrahydrofuran at reflux afforded a neutral complex [(η6-p-cymene)RuCl2(κ1-P-PPh2OH)] (1). Similarly, the reaction of [Ru(bpy)2Cl2·2H2O] (bpy = 2,2′-bipyridine) and chlorodiphenylphosphine in methanol gave a cationic complex [Ru(bpy)2Cl(κ1-P-PPh2OCH3)](PF6) (2), while treatment of [RuCl2(PPh3)3] with [2-(C5H4N)CH=N(CH2)2N(CH3)2] (L1) in tetrahydrofuran at room temperature afforded a ruthenium(II) complex [Ru(PPh3)Cl2(κ3-N,N,N-L1)] (3). Interaction of the chloro-bridged complex [Ru(CO)2Cl2]n with one equivalent of [Ph2P(o-C6H4)CH=N(CH2)2N(CH3)2] (L2) led to the isolation of [Ru(CO)Cl2(κ3-P,N,N-L2)] (4). The molecular structures of the ruthenium(II) complexes 1–4 have been determined by single-crystal X-ray crystallography. The properties of the ruthenium(II) complex 4 as a hydrogenation catalyst for acetophenone were also tested.

On the selective aerobic oxidation of benzyl alcohol with Pd/Au-nanoparticles in batch and flow

2014 ◽  
Vol 3 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Hannes Alex ◽  
Norbert Steinfeldt ◽  
Klaus Jähnisch ◽  
Matthias Bauer ◽  
Sandra Hübner
Keyword(s):  
Catalytic Activity ◽  
Benzyl Alcohol ◽  
Aerobic Oxidation ◽  
X Ray ◽  
X Ray Scattering ◽  
Oxidation Of Benzyl Alcohol ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Selective Aerobic Oxidation

AbstractNanoparticles (NP) have specific catalytic properties, which are influenced by parameters like their size, shape, or composition. Bimetallic NPs, composed of two metal elements can show an improved catalytic activity compared to the monometallic NPs. We, herein, report on the selective aerobic oxidation of benzyl alcohol catalyzed by unsupported Pd/Au and Pd NPs at atmospheric pressure. NPs of varying compositions were synthesized and characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The NPs were tested in the model reaction regarding their catalytic activity, stability, and recyclability in batch and continuous procedure. Additionally, in situ extended X-ray absorption fine structure (EXAFS) measurements were performed in order to get insight in the process during NP catalysis.

Copper (I) 1,3-R2-3,4,5,6-tetrahydropyrimidin-2-ylidenes (R=mesityl, 2-propyl): synthesis, X-ray structures, immobilization and catalytic activity

Tetrahedron ◽  
2005 ◽  
Vol 61 (51) ◽  
pp. 12145-12152 ◽  
Author(s):  
Bhasker Bantu ◽  
Dongren Wang ◽  
Klaus Wurst ◽  
Michael R. Buchmeiser
Keyword(s):  
Catalytic Activity ◽  
X Ray
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