抄録
The adsorption and desorption behavior of NO on polycrystalline Rh was investigated by X-ray photoelectron spectroscopy (XPS) to elucidate the unique catalytic properties of Rh in the reduction of NO. After the adsorption of NO at room temperature, nitride and oxide which were the dissociatively adsorbed species of NO together with molecularly adsorbed NO were observed. A part of the nitride was comparatively easily desorbed by increasing NO pressure or by rising temperature. However, the oxide was not desorbed but diffused into the bulk of Rh with rising temperature. These XPS results implied the superiority of Rh for NO reduction in reducing atmospheres in spite of relatively low activity for direct decomposition of NO.