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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 (TiCuO x) film has been synthesized on Cu(111) and characterized by complementary experimental and theoretical methods. At sub-monolayer coverages of titanium, a Cu 2O-like phase coexists with TiCuO x and TiO x domains. When the mixed-oxide surface is exposed at elevated temperatures (600–650 K) to oxygen, the formation of a well-ordered TiCuO x film occurs. Stepwise oxidation of TiCuO x shows that the formation of the mixed-oxide is faster than that of pure Cu 2O. As the Ti coverage increases, Ti-rich islands (TiO x) form. The adsorption of CO has been used to probe the exposed surface sites on the TiO x–CuO x system, indicating the existence of a new Cu + adsorption site that is not present on Cu 2O/Cu(111). Adsorption of CO on Cu + sites of TiCuO x is thermally more stable than on Cu(111), Cu 2O/Cu(111) or TiO 2(110). The Cu + sites in TiCuO x domains are stable under both reducing and oxidizing conditions whereas the Cu 2O domains present on sub-monolayer loads of Ti canmore » be reduced or oxidized under mild conditions. Furthermore, the results presented here demonstrate novel properties of TiCuO x films, which are not present on Cu(111), Cu 2O/Cu(111), or TiO 2(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
Authors:
 [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:
Report Number(s):
BNL-111953-2016-JA
Journal ID: ISSN 0920-5861; R&D Project: CO009; KC0302010
Grant/Contract Number:
SC00112704; SC0012704
Type:
Accepted Manuscript
Journal Name:
Catalysis Today
Additional Journal Information:
Journal Volume: 263; Journal Issue: C; Journal ID: ISSN 0920-5861
Publisher:
Elsevier
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
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; IRRAS; mixed-metal oxides; CO; copper; titanium; catalysis
OSTI Identifier:
1246791
Alternate Identifier(s):
OSTI ID: 1389103