Novel Au-TiC Catalysts for CO Oxidation and Desulfurization Processes
Recent articles dealing with the physical and chemical properties of novel Au-TiC catalysts are reviewed. High-resolution photoemission, scanning tunneling microscopy and first-principles periodic density-functional calculations were used to study the deposition of gold on a TiC(0 0 1) surface. Gold grows forming two-dimensional (very low coverage) and three-dimensional (medium and large coverage) islands on the carbide substrate. A positive shift in the binding energy of the C 1s core level is observed after the deposition of Au on TiC(0 0 1). The results of the density-functional calculations corroborate the formation of Au-C bonds. In general, the bond between Au and the TiC(0 0 1) surface exhibits very little ionic character, but there is a substantial polarization of electrons around Au that facilitates bonding of the adatoms with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). Experimental measurements indicate that Au/TiC(0 0 1) is a very good catalysts for the oxidation of CO, the destruction of SO{sub 2} and the hydrodesulfurization of thiophene. At temperatures below 200 K, Au/TiC(0 0 1) is able to perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction and the full decomposition of SO{sub 2}. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(0 0 1) or Au(1 1 1), a Au/TiC(0 0 1) surface displays a hydrodesulfurization activity higher than that of conventional Ni/MoS{sub x} catalysts. Metal carbides are excellent supports for enhancing the chemical reactivity of gold. The Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces.
- Research Organization:
- Brookhaven National Laboratory (BNL) National Synchrotron Light Source
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1019577
- Report Number(s):
- BNL--90970-2011-JA; KC0302010
- Journal Information:
- Catalysis Today, Journal Name: Catalysis Today Journal Issue: 1 Vol. 166; ISSN 0920-5861; ISSN CATTEA
- Country of Publication:
- United States
- Language:
- English
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Desulfurization of Thiophene on Au/TiC(001): Au−C Interactions and Charge Polarization
Related Subjects
BINDING ENERGY
BONDING
CARBIDES
CATALYSTS
CHEMICAL PROPERTIES
DEPOSITION
DESULFURIZATION
ELECTRONS
GOLD
ISLANDS
OXIDATION
OXIDES
PERFORMANCE
PHOTOEMISSION
POLARIZATION
SCANNING TUNNELING MICROSCOPY
THIOPHENE
TITANIUM CARBIDES
VALENCE
national synchrotron light source