摘要
The active sites of samarium orthovanadate(SmVO 4) were studied by means of ESR, NO TPD and temperature programmed 18 O 2 isotope exchange(TPIE) methods. The results of ESR and NO TPD confirm the presence of V 4+ in the catalyst. The TPIE revealed that the 18 O 2 isotope exchange was carried out through a single exchange procedure. The V 4+ species associated with oxygen vacancies are the sites for O 2 activation.