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Title: How to stabilize highly active Cu+ cations in a mixed-oxide catalyst

Mixed-metal oxides exhibit novel properties that are not present in their isolated constituent metal oxides and play a significant role in heterogeneous catalysis. In this study, a titanium-copper mixed-oxide (TiCuOx) film has been synthesized on Cu(111) and characterized by complementary experimental and theoretical methods. At sub-monolayer coverages of titanium, a Cu2O-like phase coexists with TiCuOx and TiOx domains. When the mixed-oxide surface is exposed at elevated temperatures (600–650 K) to oxygen, the formation of a well-ordered TiCuOx film occurs. Stepwise oxidation of TiCuOx shows that the formation of the mixed-oxide is faster than that of pure Cu2O. As the Ti coverage increases, Ti-rich islands (TiOx) form. The adsorption of CO has been used to probe the exposed surface sites on the TiOx–CuOx system, indicating the existence of a new Cu+ adsorption site that is not present on Cu2O/Cu(111). Adsorption of CO on Cu+ sites of TiCuOx is thermally more stable than on Cu(111), Cu2O/Cu(111) or TiO2(110). The Cu+ sites in TiCuOx domains are stable under both reducing and oxidizing conditions whereas the Cu2O domains present on sub-monolayer loads of Ti can be reduced or oxidized under mild conditions. Furthermore, the results presented here demonstrate novel properties of TiCuOx films, whichmore » are not present on Cu(111), Cu2O/Cu(111), or TiO2(110), and highlight the importance of the preparation and characterization of well-defined mixed-metal oxides in order to understand fundamental processes that could guide the design of new materials.« less
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [5] ;  [1] ;  [1] ;  [6] ;  [1] ;  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. State Univ. of New York (SUNY), Stony Brook, NY (United States)
  3. Chungnam National Univ., Daejeon (Korea)
  4. James Madison Univ., Harrisonburg, VA (United States)
  5. BMCC-CUNY, New York, NY (United States)
  6. Columbia Univ., New York, NY (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0920-5861; R&D Project: CO009; KC0302010
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Catalysis Today
Additional Journal Information:
Journal Volume: 263; Journal Issue: C; Journal ID: ISSN 0920-5861
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY IRRAS; mixed-metal oxides; CO; copper; titanium; catalysis