(488a) NO Reduction By H2 On Platinum Catalysts: Fundamental Mechanistic Studies

The catalytic conversion of nitric oxide, an unwanted byproduct of the combustion of hydrocarbons in air, to inert N₂ is of fundamental and practical importance.¹  Platinum catalysts, when utilized for the low temperature reduction of NO by H₂, demonstrate high conversion of NO but low selectivity toward N₂ and unfavorable production of side-products, namely N₂O and NH₃.² In this study, we combine experimental reaction kinetic studies, periodic, self-consistent Density Functional Theory calculations, and microkinetic modeling to understand the origin of the activity and selectivity of Pt in NO reduction by H₂.  Multiple Pt facets are considered to elucidate the reaction structure sensitivity.  The detailed reaction mechanism, including the role of hydrogen in NO activation, is described. Due to the strong adsorption of NO on Pt, the effect of NO coverage on the surface chemistry is accounted for in the DFT calculations, and accordingly, in the microkinetic model.

1.  Heck, R. M.; Farrauto, S. T.; Gulati, S. T., Catalytic Air Pollution Control: Commercial Technology Wiley, New Jersey 2009.

2.  H. G. Stenger, J. S. Hepburn, Energy & Fuels 1987, 1, 412.