NO adsorption study on the distribution of Ni2 + ions on the various micro-environments of carriers

The decrease of the electron density in the d orbits of Ni2 + ions, resulting from the disturbance of micro-environments in which Ni2+ ions are located, makes the frequency of adsorbed NO shlft higher. The shift degree is determined mainly by the property of the microenvironments. When Ni2+ ions are located onSII,SII(SI) sites of Y zeolite or on the surface of γ-alumina, their NO adsorption gives rise to IR bands at 1 905, 1 900 and 1 855–1 875 cm−1, respectively. The distribution of Ni2+ ions on the various micro-environments of USY zeolite, Al2O3 and MS mixed carrier has also been discussed according to the different frequencies of adsorbed NO, as well as the influence of NiO loading.