Modeling of Direct and H-Assisted NO Dissociation over Pd(110)
The First International Symposium on Quantum Science and Technology
24-27 Jun 2018
|| Bryliakova Anna Aleksandrovna
, Matveev Andrey Victorovich
Boreskov Institute of Catalysis SB RAS
Novosibirsk State University
The NO reduction on the platinum group metals surfaces is still interesting subject due to the global problem of the selective low-temperature conversion of unwanted NOx emissions from automobiles and from power plants to harmless N2. The Pd(110) surface, having steps and narrow terraces (111), is a good model for the surface of metal nanoparticles in supported catalysts. Our experimental results show that NO dissociation is rate-limiting step of NO reduction by CO or hydrogen on Pd(110) [1, 2], therefore a detailed study of this step seems to be useful for developing fundamental aspects in the field of catalysis by platinum group metals. In this work, the reaction routes of direct and H-assisted NO dissociation on Pd(110) have been considered by the climbing image nudge elastic band method based on density functional theory. It has been shown the NO dissociation from the most stable short bridge site and H-assisted N-O scission are characterized by large activation barriers and highly disfavored. The modeling of NO dissociation via NOH-intermediate shows that NOH is not formed, NO and H atoms remains coadsorbed. The calculations permit to suggest the possibility of HNO-intermediate formation, but the energy barrier of back reaction is rather less then the barriers of further N-O bond breaking reactions. The results shows NO dissociation from the most stable short bridge site characterized by the binding energy of –1.94 eV occurs via the intermediates in on-top and long bridge modes with lower binding energy from –1.31 to -1.65 eV.