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An Investigation into the Effects of Mn Promotion on the Activity and Selectivity of Co/SiO 2 for Fischer–Tropsch Synthesis: Evidence for Enhanced CO Adsorption and Dissociation

Journal Article · · ACS Catalysis
 [1];  [1];  [2]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering
  2. Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Mn is an effective promoter for improving the activity and selectivity of Co-based Fischer-Tropsch synthesis (FTS) catalysts, but the mechanism by which this promoter functions is poorly understood. The work reported here was aimed at defining the manner in which Mn interacts with Co and determining how these interactions affect the activity and selectivity of Co. Detailed measurements are reported for the kinetics of FTS as a function of Mn/Co ratio, temperature, and reactant partial pressure. These data are described by a single, two-parameter rate expression. Mn promotion was found to increase both the apparent rate constant for CO consumption and the CO adsorption constant. Further evidence for enhanced CO adsorption and dissociation was obtained from measurements of temperature-programmed desorption of CO and CO disproportionation rates, respectively. Quantitative analysis of elemental maps obtained by STEM-EDS revealed that the promoter accumulates preferentially on the surface of Co nanoparticles at low Mn loadings, resulting in a rapid onset of improvements in the product selectivity as the Mn loading increases. Furthermore, for catalysts prepared with loadings higher than Mn/Co = 0.1, the additional Mn accumulates in the form of nanometer-scale particles of MnO on the support. In situ IR spectra of adsorbed CO show that Mn promotion increases the abundance of adsorbed CO with weakened C-O bonds. It is proposed that the cleavage of the C-O bond is promoted through Lewis acid-base interactions between the Mn 2+ cations located at the edges of MnO islands covering the Co nanoparticles and the O atom of CO adsorbates adjacent to the MnO islands. Finally, the observed decrease in selectivity to CH 4 and the increased selectivity to C 5+ products with increasing Mn/Co ratio are attributed to a decrease in the ratio of adsorbed H to CO on the surface of the supported Co nanoparticles.
Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
AC02-05CH11231; AC02-06CH11357
OSTI ID:
1416909
Alternate ID(s):
OSTI ID: 1225093
Journal Information:
ACS Catalysis, Journal Name: ACS Catalysis Journal Issue: 10 Vol. 5; ISSN 2155-5435
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English

References (68)

Development of Novel Catalysts for Fischer-Tropsch Synthesis: Tuning the Product Selectivity journal July 2010
The Influence of Preparation Method on Mn-Co Interactions in Mn/Co/TiO2 Fischer-Tropsch Catalysts journal June 2010
Turnover Numbers and Soluble Metal Nanoparticles journal June 2011
Studies of Cobalt Particle Size Effects on Fischer-Tropsch Synthesis over Core-Shell-Structured Catalysts journal October 2013
CO hydrogenation over supported cobalt catalysts: FTIR and gravimetric studies journal April 1995
Manganese oxide supported cobalt-nickel catalysts for carbon monoxide hydrogenation journal February 1985
In Situ XRD Study of the Influence of Thermal Treatment on the Characteristics and the Catalytic Properties of Cobalt-Based Fischer–Tropsch Catalysts journal January 2002
Hydrogen adsorption on supported cobalt, iron, and nickel journal January 1991
Promotion and support effects in syngas reactions journal January 1991
Hydrogenation of CO2, acetone, and CO on a Rh foil promoted by titania overlayers journal January 1990
Lewis acidity as an explanation for oxide promotion of metals: implications of its importance and limits for catalytic reactions journal January 1994
The Co-Mn (Cobalt-Manganese) system journal April 1990
A pre-edge analysis of Mn K-edge XANES spectra to help determine the speciation of manganese in minerals and glasses journal July 2008
In-Situ Electron Energy Loss Spectroscopy Study of Mn-Promoted Co/TiO2 Fischer–Tropsch Catalysts journal February 2011
A Highly Active and Selective Manganese Oxide Promoted Cobalt-on-Silica Fischer–Tropsch Catalyst journal August 2011
The stoichiometries of H2 and CO adsorptions on cobalt: Effects of support and preparation journal January 1984
Promoter action in Fischer-Tropsch catalysis journal April 1985
Chemisorption studies on cobalt single crystal surfaces journal October 1977
Surface free energies of solid metals: Estimation from liquid surface tension measurements journal January 1977
Thermal desorption of gases journal July 1962
Carbon monoxide hydrogenation over carbon supported cobalt or ruthenium catalysts. promoting effects of magnesium, vanadium and cerium oxides journal December 1994
Adsorption and structure dependent desorption of CO on Co(0001) journal December 1998
Hydrogenation of carbon monoxide on carbon-supported cobalt rare earth catalysts journal March 1986
Interpretation of Measurements in Experimental Catalysis book January 1954
Design, synthesis, and use of cobalt-based Fischer-Tropsch synthesis catalysts journal November 1997
Promotion of Co/SiO2 Fischer–Tropsch catalysts with zirconium journal January 2003
Heats of adsorption of linearly adsorbed CO species on Co2+ and Co° sites of reduced Co/Al2O3 catalysts in relationship with the CO/H2 reaction journal November 2012
Particle size distributions in heterogeneous catalysts: What do they tell us about the sintering mechanism? journal January 2006
Identification of the active species in the working alumina-supported cobalt catalyst under various conditions of Fischer–Tropsch synthesis journal April 2011
Microcalorimetric studies of H2 and CO on Co/γ-Al2O3 catalysts for Fischer–Tropsch synthesis journal October 2013
Fischer–Tropsch synthesis: Activity of metallic phases of cobalt supported on silica journal October 2013
Mn promotion effects in Co/TiO Fischer?Tropsch catalysts as investigated by XPS and STEM-EELS journal March 2005
Investigation of promoter effects of manganese oxide on carbon nanofiber-supported cobalt catalysts for Fischer–Tropsch synthesis journal January 2006
Effects of manganese oxide promoter on the CO and H2 adsorption properties of titania-supported cobalt Fischer–Tropsch catalysts journal February 2007
Cobalt species in promoted cobalt alumina-supported Fischer–Tropsch catalysts journal December 2007
Selective adsorption of manganese onto cobalt for optimized Mn/Co/TiO2 Fischer–Tropsch catalysts journal March 2010
CO activation pathways and the mechanism of Fischer–Tropsch synthesis journal June 2010
Effects of Mn promotion on the activity and selectivity of Co/SiO2 for Fischer–Tropsch Synthesis journal April 2012
Investigations of element spatial correlation in Mn-promoted Co-based Fischer–Tropsch synthesis catalysts journal August 2015
Kinetic study of Fischer–Tropsch process on titania-supported cobalt–manganese catalyst journal November 2010
Kinetics studies of nano-structured cobalt–manganese oxide catalysts in Fischer–Tropsch synthesis journal July 2013
Effects of manganese and reduction promoters on carbon nanotube supported cobalt catalysts in Fischer–Tropsch synthesis journal December 2012
Advances in the Development of Novel Cobalt Fischer−Tropsch Catalysts for Synthesis of Long-Chain Hydrocarbons and Clean Fuels journal May 2007
Intrinsic kinetics of the Fischer-Tropsch synthesis on a cobalt catalyst journal January 1991
Carbon monoxide hydrogenation using cobalt manganese oxide catalysts: initial catalyst optimization studies journal August 1988
Catalytic site requirements for elementary steps in syngas conversion to oxygenates over promoted rhodium journal September 1986
XPS studies of solvated metal atom dispersed (SMAD) catalysts. Evidence for layered cobalt-manganese particles on alumina and silica journal January 1991
An EXAFS study of cobalt-manganese/silica bimetallic solvated metal atom dispersed (SMAD) catalysts journal August 1988
Cobalt Particle Size Effects in the Fischer−Tropsch Reaction Studied with Carbon Nanofiber Supported Catalysts journal March 2006
On the Origin of the Cobalt Particle Size Effects in Fischer−Tropsch Catalysis journal April 2009
FTIR Study of Adsorption and Photoassisted Oxygen Isotopic Exchange of Carbon Monoxide, Carbon Dioxide, Carbonate, and Formate on TiO 2 journal October 2002
The Structure and Reactivity of Al 2 O 3 -Supported Cobalt−Palladium Particles:  A CO-TPD, STM, and XPS Study journal December 2002
In Situ X-ray Absorption of Co/Mn/TiO 2 Catalysts for Fischer−Tropsch Synthesis journal October 2004
X-ray Absorption Spectroscopy of Mn/Co/TiO 2 Fischer−Tropsch Catalysts:  Relationships between Preparation Method, Molecular Structure, and Catalyst Performance journal May 2006
Reactivity of CO on Carbon-Covered Cobalt Surfaces in Fischer–Tropsch Synthesis journal March 2014
A Combined in - Situ PM-RAIRS and Kinetic Study of Single-Crystal Cobalt Catalysts under Synthesis Gas at Pressures up to 300 mbar journal May 1997
Phase Equilibria in the Co–Mn–Ti–O System over Wide Ranges of Temperatures and Oxygen Pressures journal January 2002
Gd promotion of Co/SiO2 Fischer–Tropsch synthesis catalysts journal January 2001
Combined EXAFS and STEM-EELS study of the electronic state and location of Mn as promoter in Co-based Fischer–Tropsch catalysts journal January 2005
Structure sensitivity of the Fischer–Tropsch reaction; molecular kinetics simulations journal January 2011
Infrared and X-ray photoelectron spectroscopy studies of carbon monoxide adsorbed on silica-supported cobalt catalysts
  • Sato, Kimihiko; Inoue, Yasunobu; Kojima, Isao
  • Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, Vol. 80, Issue 4 https://doi.org/10.1039/f19848000841
journal January 1984
CO hydrogenation using cobalt/manganese oxide catalysts. Comments on the mechanism of carbon–carbon bond formation
  • Hutchings, Graham J.; van der Riet, Mark; Hunter, Roger
  • Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, Vol. 85, Issue 9 https://doi.org/10.1039/f19898502875
journal January 1989
The New MRCAT (Sector 10) Bending Magnet Beamline at the Advanced Photon Source
  • Kropf, A. J.; Katsoudas, J.; Chattopadhyay, S.
  • SRI 2009, 10TH INTERNATIONAL CONFERENCE ON RADIATION INSTRUMENTATION, AIP Conference Proceedings https://doi.org/10.1063/1.3463194
conference January 2010
EXAFS analysis using FEFF and FEFFIT journal March 2001
ATHENA , ARTEMIS , HEPHAESTUS : data analysis for X-ray absorption spectroscopy using IFEFFIT journal June 2005
Fischer–Tropsch Synthesis with Supported Cobalt Catalyst. Promoting Effects of Lanthanum Oxide for Cobalt/Silica Catalyst journal June 1996
Microstructure of Supported Cobalt Fischer-Tropsch Catalysts journal October 2008
Promotion of Cobalt Fischer-Tropsch Catalysts with Noble Metals: a Review journal November 2008

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