Models of Active VPO Surface

Hutchings et al [64] and Volta et al [65] suggested that the actives sites for 

Cavani and Trifiro [13] further described four types of termination of the 

Ebner and Thompson [58] proposed the termination of the surface with pendant H2P207 groups, which surround two vanadyl dimers (type B). Such surface termination may be envisioned by replacing every phosphate tetrahedron facing up in the bulk (200) planes of (V0)2P207 with pyrophosphate groups. In this type of surface termination, the pyrophosphate fence isolates pairs of vanadyl dimers from other pairs, which was proposed to be beneficial for the selectivity to maleic anhydride during n-butane oxidation. 

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