Effect of carbon support on the catalytic performance of Cu-based nanoparticles for oxidative carbonylation of methanol

To obtain selective hydrogenation catalysts with low noble metal content, two carbon-supported Mo-Pt bimetallic catalysts have been synthesized from two different molybdenum precursors, i.e., Na2MoO4 and (NH4)6Mo7O24. The results obtained by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) combined with the presence and strength of acid sites clarified the different catalytic behavior toward cinnamaldehyde hydrogenation. After impregnating the carbon support with Mo precursors, each sample was used either as is or treated at 400 °C in N2 flow, as support for Pt nanoparticles (NPs). The heating treatment before Pt deposition had a positive effect on the catalytic performance. Indeed, TEM analyses showed very homogeneously dispersed Pt NPs only when they were deposited on the heat-treated Mo/C supports, and XPS analyses revealed an increase in both the exposure and reduction of Pt, which was probably tuned by different MoO3/MoO2 ratios. Moreover, the different acid properties of the catalysts resulted in different selectivity.

Download Full-text

Preparation and Electrocatalytic Characteristics Research of Pd/C Catalyst for Direct Ethanol Fuel Cell

Journal of Chemistry ◽

10.1155/2013/250760 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Qiao Xia Li ◽

Ming Shuang Liu ◽

Qun Jie Xu ◽

Hong Min Mao

Keyword(s):

Fuel Cell ◽

Average Particle Size ◽

Active Surface ◽

Carbon Support ◽

Catalytic Performance ◽

Active Surface Area ◽

Average Particle ◽

Ethanol Fuel ◽

Direct Ethanol Fuel Cell ◽

Electrochemical Active Surface Area

Two kinds of carbon-support 20% Pd/C catalysts for use in direct ethanol fuel cell (DEFC) have been prepared by an impregnation reduction method using NaBH4and NaH2PO2as reductants, respectively, in this study. The catalysts were characterized by XRD and TEM. The results show that the catalysts had been completely reduced, and the catalysts are spherical and homogeneously dispersed on carbon. The electrocatalytic activity of the catalysts was investigated by electrochemical measurements. The results indicate that the catalysts had an average particle size of 3.3 nm and showed the better catalytic performance, when NaBH4was used as the reducing agent. The electrochemical active surface area of Pd/C (NaBH4) was 56.4 m2·g−1. The electrochemical activity of the Pd/C (NaBH4) was much higher than that of Pd/C (NaH2PO2).

Download Full-text

Oxidative Carbonylation of Methanol to Dimethyl Carbonate by Chlorine-Free Homogeneous and Immobilized 2,2'-Bipyrimidine Modified Copper Catalyst

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20071094 ◽

2007 ◽

Vol 72 (8) ◽

pp. 1094-1106 ◽

Cited By ~ 18

Author(s):

Szilárd Csihony ◽

László T. Mika ◽

Gábor Vlád ◽

Katalin Barta ◽

Christian P. Mehnert ◽

...

Keyword(s):

High Pressure ◽

Dimethyl Carbonate ◽

Copper Catalyst ◽

Catalytic Performance ◽

Spectroscopic Studies ◽

Oxidative Carbonylation ◽

Cu Catalyst

A chlorine-free catalyst, prepared in situ from Cu(II) acetate and 2,2'-bipyrimidine, can be used for the oxidative carbonylation of methanol to dimethyl carbonate. In situ high pressure IR and NMR spectroscopic studies suggest the formation of [Cu(2,2'-bipyrimidine)(CO)- (OMe)] as one of the key intermediates. The catalytic performance of the 2,2'-bipyrimidine-modified Cu-catalyst is similar to the CuCl-based system. The chlorine free catalyst can be immobilized by using the copolymer of 5-vinyl-2,2'-bipyrimidine and styrene.

Download Full-text

Thermal Modification Effect on Supported Cu-Based Activated Carbon Catalyst in Hydrogenolysis of Glycerol

Materials ◽

10.3390/ma13030603 ◽

2020 ◽

Vol 13 (3) ◽

pp. 603 ◽

Cited By ~ 1

Author(s):

Juan Seguel ◽

Rafael García ◽

Ricardo José Chimentão ◽

José Luis García-Fierro ◽

I. Tyrone Ghampson ◽

...

Keyword(s):

Activated Carbon ◽

Specific Surface ◽

Hydrogen Adsorption ◽

Carbon Support ◽

Catalytic Performance ◽

Homogeneous Distribution ◽

Surface Groups ◽

Carbon Supports ◽

Surface Areas ◽

Oxygen Surface

Glycerol hydrogenolysis to 1,2-propanediol (1,2-PDO) was performed over activated carbon supported copper-based catalysts. The catalysts were prepared by impregnation using a pristine carbon support and thermally-treated carbon supports (450, 600, 750, and 1000 °C). The final hydrogen adsorption capacity, porous structure, and total acidity of the catalysts were found to be important descriptors to understand catalytic performance. Oxygen surface groups on the support controlled copper dispersion by modifying acidic and adsorption properties. The amount of oxygen species of thermally modified carbon supports was also found to be a function of its specific surface area. Carbon supports with high specific surface areas contained large amount of oxygen surface species, inducing homogeneous distribution of Cu species on the carbon support during impregnation. The oxygen surface groups likely acted as anchorage centers, whereby the more stable oxygen surface groups after the reduction treatment produced an increase in the interaction of the copper species with the carbon support, and determined catalytic performances.

Download Full-text