Chromium oxide catalysts for COx-free hydrogen generation via catalytic ammonia decomposition

Chromium oxide nanocrystallites have been synthesized by thermal decomposition of solid precursors and evaluated as catalysts for ammonia decomposition. The physical and chemical properties of Cr2O3 catalysts are characterized by various techniques such as N2 adsorption–desorption isotherms, XRD, TEM, and XPS. The relationship between catalytic activities and physicochemical and electronic properties of Cr2O3 catalysts is investigated. The Cr2O3 catalysts are active for ammonia decomposition and the activity is structure-sensitive with a close relation to particle size. During the ammonia decomposition reaction, N atoms are inserted into the Cr2O3 catalyst thus enhancing the activity of catalyst, due to the variation in the physical, chemical and electronic structures of Cr2O3 catalysts.

Graphical abstractMesoporous chromium oxide catalysts have been synthesized and evaluated for ammonia decomposition. The NH3 decomposition on the Cr2O3 catalysts is structure-sensitive and the most active catalyst has a large particle size. Moreover, interstitial CrNxOy compounds have been found to act as the active sites for the NH3 decomposition.Figure optionsDownload full-size imageDownload as PowerPoint slide