STUDY OF CARRIER EFFECTS ON THE ESR OF VANADIUM IONS FORMED IN SUPPORTED CATALYSTS, AS ASSISTED BY SPECTRUM CALCULATION

In order to study the carrier effects on the supported catalysts of vanadium, the ESR spectra of vanadium ions supported on gamma -Al//2O//3, SiO//2, ZrO//2, TiO//2, MgO, or CaO and reduced in H//2 at 500 degree C were studied. When gamma -Al//2O//3, SiO//2, ZrO//2, or TiO//2 were used as the carriers, the main spectral component could be assigned to the V**4** plus ion. The results of data analysis, assisted by spectrum calculation, showed that, on catalyst which had a high activity in the reduction of NO//x by NH//3, the V**4** plus ion had a highly populated d//x//y orbital, while on catalyst of low activity, V**4** plus had a d//x//y with a low spin density. If the carrier was MgO, the V ion was reduced to V**2** plus . If the carrier was CaO, no ESR signals due to V ions are observed.