ChemInform Abstract: Reduction and Oxidation Effects on Rhodium Species in Na-X Zeolite Studied by Electron Spin Echo and Electron Spin Resonance Spectroscopies.
Abstract
Oxidation and reduction of RhNa-Xsamples activated in flowing oxygen allow the indirect detection of Rh(III) and Rh(I) species generated during activation, A new set of paramagnetic species is produced differing in both location and symmetry from the known species Aand C. Two species are formed by H2 reduction: H1 (activation temp. 240-400°C) and H2 (400-500°C).
ChemInform Abstract
Oxidation and reduction of RhNa-Xsamples activated in flowing oxygen allow the indirect detection of Rh(III) and Rh(I) species generated during activation, A new set of paramagnetic species is produced differing in both location and symmetry from the known species Aand C. Two species are formed by H2 reduction: H1 (activation temp. 240-400°C) and H2 (400-500°C). H1 is located in the α-cage and has either cubic or trigonal symmetry; H2 is located either in the hexagonal prism or in the β-cage. Oxidation of the activated samples generates species loeated in the β-cage which respond to the adsorption of H2O, MeOH, or NH3.
