Supported vanadium oxides serve as a substitutional catalyst for both propane nonoxidative dehydrogenation (PDH) and oxidative dehydrogenation (ODH), resulting from their substantial activity, propene selectivity, and regeneration rate. However, the nature of the active sites under reaction conditions is still under debate. This paper describes the structure–performance relationships of supported vanadium oxides at different degrees of polymerization by combined density function theory (DFT) and experimental studies. We found that when we expose the vanadium oxides to the pure propane gas, the reaction process can be divided into two periods: the initial oxidative dehydrogenation (ODH) dominant period and subsequent nonoxidative dehydrogenation (PDH) dominant period. In the ODH dominant period, the vanadium oxides tend to lose the top oxygen (V═O), while in the PDH dominant period, the vanadium oxides are relatively stable. Electronic structure analysis indicates that the oxygen p-band center correlates with the dehydrogenation barrier on the oxygen site, which is useful to predict its dehydrogenation activity.
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