Selective Reduction of NO into N-2 Catalyzed by Rh-1-Doped Cluster Anions RhCe2O3-5 (-)

Catalytic conversion of toxic nitrogen oxide (NO) andcarbon monoxide(CO) into nitrogen (N-2) and carbon dioxide (CO2) is imperative under the weight of the increasingly stringent emissionregulations, while a fundamental understanding of the nature of theactive site to selectively drive N-2 generation is elusive.Herein, in combination with state-of-the-art mass-spectrometric experimentsand quantum-chemical calculations, we demonstrated that the rhodium-ceriumoxide clusters RhCe2O3-5 (-) can catalytically drive NO reduction by CO and give rise to N-2 and CO2. This finding represents a sharp improvementin cluster science where N2O is commonly produced in therarely established examples of catalytic NO reduction mediated withgas-phase clusters. We demonstrated the importance of the unique chemicalenvironment in the RhCe2O3 (-) cluster to guide the substantially improved N-2 selectivity:a triatomic Lewis "acid-base-acid" Ce & delta;+-Rh & delta;--Ce & delta;+ site is proposed to strongly adsorb two NO moleculesas well as the N2O intermediate that is attached on theRh atom and can facilely dissociate to form N-2 assistedby both Ce atoms.