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Title: Elementary steps in CO hydrogenation on Rh catalysts supported on ZrO[sub 2] and Mo/ZrO[sub 2]

Abstract

The first steps of CO activation and hydrogenation reactions on Rh catalysts have been studied in order to identify possible intermediates in the reaction pathway to C[sub 1] compounds. Rh catalysts were prepared by supporting Rh[sub 4](CO)[sub 12] or on ZrO[sub 2] after adsorption of Mo(CO)[sub 6]. The Rh content on all catalysts was 1% (w/w) while the Mo/Rh atomic ratio ranged from 0.0 to 2.0. The supported catalysts were decomposed in H[sub 2] at 523 K (LTR) and at 773 K (HTR). The samples were characterized by TEM, EPR, FTIR, and chemisorption of H[sub 2], O[sub 2], and CO. The catalytic activity was tested in the CO hydrogenation reaction at 493 K and 101 kPa. The total CO conversion increased with Mo/Rh ration on LTR catalysts while it was unaffected on HTR catalysts. By increasing the Mo content the amount of CO[sub 2] formed increased significantly. The CO carbon efficiency to methane and total hydrocarbon without CO[sub 2], did not depend on the Mo/Rh ratio for LTR catalysts while a constant decrease was observed for HTR catalysts. The carbon efficiency to methanol increased with the Mo content both on LTR and HTR catalysts, and that to ethanol changed withmore » the Mo/Rh ratio and the activation temperature. The environment of Rh particles is strongly modified by the presence of Mo as evidenced by modification of the IR spectrum of chemisorbed CO both in the linear and in the bridged Rh-CO region. On the basis of the experimental results the reaction paths to CO[sub 2], CH[sub 3]OH, and CH[sub 4], and the effect of MoO[sub 3] promoter are discussed in detail. The methane formation through different pathways involving a bicarbonate and/or a formate intermediate are presented. 80 refs., 13 figs., 1 tab.« less

Authors:
;  [1]; ;  [2]; ;  [3]
  1. Universita di Torino (Italy)
  2. Univ. di Venzia Dorsoduro (Italy)
  3. Universita di Milano (Italy)
Publication Date:
OSTI Identifier:
7036612
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis; (United States)
Additional Journal Information:
Journal Volume: 146:2; Journal ID: ISSN 0021-9517
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 01 COAL, LIGNITE, AND PEAT; 10 SYNTHETIC FUELS; CARBON MONOXIDE; CHEMISORPTION; HYDROGENATION; HYDROGEN; OXYGEN; RHODIUM; CATALYTIC EFFECTS; ABSORPTION SPECTROSCOPY; CATALYST SUPPORTS; ELECTRON MICROSCOPY; ELECTRON SPIN RESONANCE; MOLYBDENUM OXIDES; REACTION INTERMEDIATES; SORPTIVE PROPERTIES; ZIRCONIUM OXIDES; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHEMICAL REACTIONS; ELEMENTS; MAGNETIC RESONANCE; METALS; MICROSCOPY; MOLYBDENUM COMPOUNDS; NONMETALS; OXIDES; OXYGEN COMPOUNDS; PLATINUM METALS; REFRACTORY METAL COMPOUNDS; RESONANCE; SEPARATION PROCESSES; SORPTION; SPECTROSCOPY; SURFACE PROPERTIES; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS; ZIRCONIUM COMPOUNDS; 400201* - Chemical & Physicochemical Properties; 010408 - Coal, Lignite, & Peat- C1 Processes- (1987-); 100200 - Synthetic Fuels- Production- (1990-)

Citation Formats

Guglielminotti, E, Giamello, E, Pinna, F, Strukul, G, Martinengo, S, and Zanderighi, L. Elementary steps in CO hydrogenation on Rh catalysts supported on ZrO[sub 2] and Mo/ZrO[sub 2]. United States: N. p., 1994. Web. doi:10.1006/jcat.1994.1080.
Guglielminotti, E, Giamello, E, Pinna, F, Strukul, G, Martinengo, S, & Zanderighi, L. Elementary steps in CO hydrogenation on Rh catalysts supported on ZrO[sub 2] and Mo/ZrO[sub 2]. United States. https://doi.org/10.1006/jcat.1994.1080
Guglielminotti, E, Giamello, E, Pinna, F, Strukul, G, Martinengo, S, and Zanderighi, L. Fri . "Elementary steps in CO hydrogenation on Rh catalysts supported on ZrO[sub 2] and Mo/ZrO[sub 2]". United States. https://doi.org/10.1006/jcat.1994.1080.
@article{osti_7036612,
title = {Elementary steps in CO hydrogenation on Rh catalysts supported on ZrO[sub 2] and Mo/ZrO[sub 2]},
author = {Guglielminotti, E and Giamello, E and Pinna, F and Strukul, G and Martinengo, S and Zanderighi, L},
abstractNote = {The first steps of CO activation and hydrogenation reactions on Rh catalysts have been studied in order to identify possible intermediates in the reaction pathway to C[sub 1] compounds. Rh catalysts were prepared by supporting Rh[sub 4](CO)[sub 12] or on ZrO[sub 2] after adsorption of Mo(CO)[sub 6]. The Rh content on all catalysts was 1% (w/w) while the Mo/Rh atomic ratio ranged from 0.0 to 2.0. The supported catalysts were decomposed in H[sub 2] at 523 K (LTR) and at 773 K (HTR). The samples were characterized by TEM, EPR, FTIR, and chemisorption of H[sub 2], O[sub 2], and CO. The catalytic activity was tested in the CO hydrogenation reaction at 493 K and 101 kPa. The total CO conversion increased with Mo/Rh ration on LTR catalysts while it was unaffected on HTR catalysts. By increasing the Mo content the amount of CO[sub 2] formed increased significantly. The CO carbon efficiency to methane and total hydrocarbon without CO[sub 2], did not depend on the Mo/Rh ratio for LTR catalysts while a constant decrease was observed for HTR catalysts. The carbon efficiency to methanol increased with the Mo content both on LTR and HTR catalysts, and that to ethanol changed with the Mo/Rh ratio and the activation temperature. The environment of Rh particles is strongly modified by the presence of Mo as evidenced by modification of the IR spectrum of chemisorbed CO both in the linear and in the bridged Rh-CO region. On the basis of the experimental results the reaction paths to CO[sub 2], CH[sub 3]OH, and CH[sub 4], and the effect of MoO[sub 3] promoter are discussed in detail. The methane formation through different pathways involving a bicarbonate and/or a formate intermediate are presented. 80 refs., 13 figs., 1 tab.},
doi = {10.1006/jcat.1994.1080},
url = {https://www.osti.gov/biblio/7036612}, journal = {Journal of Catalysis; (United States)},
issn = {0021-9517},
number = ,
volume = 146:2,
place = {United States},
year = {1994},
month = {4}
}