Structure and reactivity of Ru nanoparticles supported on modified graphite surfaces: a study of the model catalysts for ammonia synthesis.

摘要: Supported ruthenium metal catalysts have higher activity than traditional iron-based used industrially for ammonia synthesis. A study of a model Ru/C catalyst was carried out to advance the understanding structure and reactivity correlations in this structure-sensitive reaction where dinitrogen dissociation is rate-limiting step. Ru particles were grown by chemical vapor deposition (CVD) via Ru(3)(CO)(12) precursor on highly oriented pyrolytic graphite (HOPG) surface modified with one-atomic-layer-deep holes mimicking activated carbon support. Scanning tunneling microscopy (STM) has been investigate growth, structure, morphology particles. Thermal desorption dissociatively adsorbed nitrogen evaluate Ru/HOPG catalysts. Two different particle structures reactivities N(2) identified. The initial sticking coefficient dissociative adsorption approximately 10(-6), 4 orders larger compared that single-crystal surfaces.