Chromium oxide catalysts for CO_x-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.