J . Phys. Chem. 1992,96, 10358-10365
10358
Registry No. Cu, 7440-50-8; Cr203.1308-38-9; SO2,7631-86-9; Cr, 7440-47- 3.
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Surface Chemlstry of Magnesium Oxide-Supported Molybdenum Oxide: An In Sltu Raman Spectroscoplc Study Si-Chung Chang,*.+ M. Anne Leugers, Analytical Sciences, Michigan Research & Development, The Dow Chemical Company, I897 Building, Midland, Michigan 48667
and Simon R. Bare* Catalysis Laboratory, Central Research & Development, The Dow Chemical Company, 1776 Building, Midland, Michigan 48674 (Received: April 2, 1992)
Supported molybdenum oxide on magnesium oxide was investigatedby in situ Raman spectroscopy as a function of molybdenum loading and calcination temperature in order to determine the molecular structures of the surface molybdenum oxide species. Molybdenum loadings from 1.0 to 26.7 wt % were studied after calcination at temperatures from 8 0 to 700 O C . For samples calcined at 600 O C in dry air the observed structure of the molybdenum oxide species was dependent upon weight loading. At low molybdenum loadings (
