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Title: Highly active Au/δ-MoC and Cu/δ-MoC catalysts for the conversion of CO 2: The metal/C ratio as a key factor defining activity, selectivity, and stability

Abstract

The ever growing increase of CO 2 concentration in the atmosphere is one of the main causes of global warming. Thus, CO 2 activation and conversion toward valuable added compounds is a major scientific challenge. A new set of Au/δ-MoC and Cu/δ-MoC catalysts exhibits high activity, selectivity, and stability for the reduction of CO 2 to CO with some subsequent selective hydrogenation toward methanol. Sophisticated experiments under controlled conditions and calculations based on density functional theory have been used to study the unique behavior of these systems. A detailed comparison of the behavior of Au/β-Mo 2C and Au/δ-MoC catalysts provides evidence of the impact of the metal/carbon ratio in the carbide on the performance of the catalysts. The present results show that this ratio governs the chemical behavior of the carbide and the properties of the admetal, up to the point of being able to switch the rate and mechanism of the process for CO 2 conversion. Here, a control of the metal/carbon ratio paves the road for an efficient reutilization of this environmental harmful greenhouse gas.

Authors:
 [1];  [2];  [2];  [1];  [3];  [1];  [3]
  1. Univ. de Barcelona, Barcelona (Spain)
  2. Univ. Central de Venezuela, Caracas (Venezuela)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1326741
Report Number(s):
BNL-112632-2016-JA
Journal ID: ISSN 0002-7863; R&D Project: CP027; KC0302010
Grant/Contract Number:
SC00112704
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 138; Journal Issue: 26; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; CO2 hydrogenation; CO2 reduction; methanol; reverse water-gas shift reaction; metal carbides; copper

Citation Formats

Posada-Pérez, Sergio, Ramírez, Pedro J., Evans, Jaime, Viñes, Francesc, Liu, Ping, Illas, Francesc, and Rodriguez, José A. Highly active Au/δ-MoC and Cu/δ-MoC catalysts for the conversion of CO2: The metal/C ratio as a key factor defining activity, selectivity, and stability. United States: N. p., 2016. Web. doi:10.1021/jacs.6b04529.
Posada-Pérez, Sergio, Ramírez, Pedro J., Evans, Jaime, Viñes, Francesc, Liu, Ping, Illas, Francesc, & Rodriguez, José A. Highly active Au/δ-MoC and Cu/δ-MoC catalysts for the conversion of CO2: The metal/C ratio as a key factor defining activity, selectivity, and stability. United States. doi:10.1021/jacs.6b04529.
Posada-Pérez, Sergio, Ramírez, Pedro J., Evans, Jaime, Viñes, Francesc, Liu, Ping, Illas, Francesc, and Rodriguez, José A. 2016. "Highly active Au/δ-MoC and Cu/δ-MoC catalysts for the conversion of CO2: The metal/C ratio as a key factor defining activity, selectivity, and stability". United States. doi:10.1021/jacs.6b04529. https://www.osti.gov/servlets/purl/1326741.
@article{osti_1326741,
title = {Highly active Au/δ-MoC and Cu/δ-MoC catalysts for the conversion of CO2: The metal/C ratio as a key factor defining activity, selectivity, and stability},
author = {Posada-Pérez, Sergio and Ramírez, Pedro J. and Evans, Jaime and Viñes, Francesc and Liu, Ping and Illas, Francesc and Rodriguez, José A.},
abstractNote = {The ever growing increase of CO2 concentration in the atmosphere is one of the main causes of global warming. Thus, CO2 activation and conversion toward valuable added compounds is a major scientific challenge. A new set of Au/δ-MoC and Cu/δ-MoC catalysts exhibits high activity, selectivity, and stability for the reduction of CO2 to CO with some subsequent selective hydrogenation toward methanol. Sophisticated experiments under controlled conditions and calculations based on density functional theory have been used to study the unique behavior of these systems. A detailed comparison of the behavior of Au/β-Mo2C and Au/δ-MoC catalysts provides evidence of the impact of the metal/carbon ratio in the carbide on the performance of the catalysts. The present results show that this ratio governs the chemical behavior of the carbide and the properties of the admetal, up to the point of being able to switch the rate and mechanism of the process for CO2 conversion. Here, a control of the metal/carbon ratio paves the road for an efficient reutilization of this environmental harmful greenhouse gas.},
doi = {10.1021/jacs.6b04529},
journal = {Journal of the American Chemical Society},
number = 26,
volume = 138,
place = {United States},
year = 2016,
month = 6
}

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Cited by: 6works
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  • X-ray photoelectron and ESR spectroscopy was used to study the distribution and state of the active component on the support surface after the heterogenization of cupric chloride on lithium-modified silica gel. The chemisorption of CuC1/sub 2/ is mainly insular in nature. The catalytic activity of the catalysts obtained was studied in the liquid-phase oxidation of cumene to give cumyl hydroperoxide. The nature of the dependence of the specific catalytic activity on the surface concentration of the supported halide may be explained assuming insular nature for the chemisorption of CuC1/sub 2/. A comparison was carried out for the catalytic activity, selectivitymore » and stability of the catalyst obtained with its impregnation analog and a number of significant advantages of the former were found relative to all these parameters.« less
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  • Here, the conversion of CO 2 into methanol catalyzed by β-Mo 2C and Cu/β-Mo 2C surfaces has been investigated by means of a combined experimental and theoretical study. Experiments have shown the direct activation and dissociation of the CO 2 molecule on bare β-Mo 2C, whereas on Cu/β-Mo 2C, CO 2 must be assisted by hydrogen for its conversion. Methane and CO are the main products on the clean surface and methanol production is lower. However, the deposition of Cu clusters avoids methane formation and increases methanol production even above that corresponding to a model of the technical catalyst. DFTmore » calculations on surface models of both possible C- and Mo-terminations corroborate the experimental observations. Calculations for the clean Mo-terminated surface reveal the existence of two possible routes for methane production (C + 4H → CH 4; CH 3O + 3H → CH 4 + H 2O) which are competitive with methanol synthesis, displaying slightly lower energy barriers. On the other hand, a model for Cu deposited clusters on the Mo-terminated surface points towards a new route for methanol and CO production avoiding methane formation. The new route is a direct consequence of the generation of a Mo 2C–Cu interface. The present experimental and theoretical results entail the interesting catalytic properties of Mo 2C as an active support of metallic nanoparticles, and also illustrate how the deposition of a metal can drastically change the activity and selectivity of a carbide substrate for CO 2 hydrogenation.« less