The role of alkali promoters in enhancing the direct N2O decomposition reactivity over NiO catalysts

Direct N2O decomposition has been investigated over bare NiO and a series of its alkali-promoted catalysts. These catalysts were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy. XPS analysis revealed that surface nickel is present in three forms: metal particles, NiO and Ni(OH)2. It is suggested that nickel(0) valent atoms are essential for the interaction with N2O molecules at the catalyst surfaces. Bare NiO exhibited a very low N2O decomposition reactivity. However, the alkali-containing catalysts exhibited a marked activity enhancement.

Graphical AbstractThe N2O decomposition on alkali-promoted NiO catalysts is investigated. Alkali cations markedly enhance the N2O decomposition reactivity over NiO. K- and Cs-doped NiO catalysts are shown to have superior activity than Li- and Na-doped catalysts.Figure optionsDownload full-size imageDownload as PowerPoint slide