Spectroscopy of Oxygen Species

Tarama, S. Teranishi, S. Yoshida, and N. Tamura, Proc. 3rd. International Congress on Catalysis, Amsterdam, 1964, ed. W. M. H. Sachtler, G. C. A. Schuit and P. Zwietering, North-HoIIand, Amsterdam, 1965, Vol. 1, p. 282. 

Somewhat outside this main line of research is the paper by Vil al ba et al.16 in which the i.r. bands in the region of 800 to 900 cm-1 in V-MgO and V-CaO are ascribed to tetrahedral VO - ions. Furthermore these authors suggest that absorptions in the range 680 to 560 cm-1 are due to (V-O-V) vibrations or to octahedral species. 

Inomata et al 23,28,59 observe a weakening or disappearance of the 1025 cm-1 line upon pulsing with NO + NH3 in the absence of oxygen with simultaneous formation of the V02 spectrum with a characteristic band at 990cm-1. Niwa et al.21 also observe a line near 1000cm-1 due to (V=0) which disappears after pulsing with toluene. 

Bielanski et al.,63 in a study of V205 and V205/Mo03 catalysts, conclude from the absence of an absorption near 1000 cm-1, for the catalysts most active and selective for benzene oxidation, that the (V=0) bond does not play a role in this reaction. 

Inomata etal31,32 observe even at relatively low vanadium contents a clear absorption at 1020 cm-1 for V2Os on Ti02. When the V205 is supported on A1203, however, this absorption is only seen as a shoulder, suggesting that the support influences the exposure of certain crystal planes as the (V= O) bond is only present in the (010) planes. 

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