NO dissociation and N-2 production in the presence of co-adsorbed (SO2)-O-18 and D-2 on Pt(332)

作者：Hu Yuhai; Griffiths Keith^*

来源：Surface Science, 2009, 603(17): 2835-2840.

DOI：10.1016/j.susc.2009.07.032

• Platinum
• deNO(x)
• Selective catalytic reduction (SCR)
• Sulfur oxide
• Hydrogen

NO dissociation and subsequent N-2 production in the presence of co-adsorbed (SO2)-O-18 and D-2 on the surface of stepped Pt(332) were studied using Fourier transform infra red reflection-absorption spectroscopy (FTIR-RAS) combined with thermal desorption spectroscopy (TDS). Reduction of NO by D (D-2 is adsorbed dissociatively on Pt surfaces) proceeds to a limited extent, because this reaction is rate-controlled by NO dissociation and the supply of D atoms at the higher surface temperatures at which NO dissociation becomes significant (350 K and higher). NO-D reaction is suppressed in the presence Of (SO2)-O-18, depending significantly on the (SO2)-O-18 coverage and the competition between the reactions NO-D and (SO2)-O-18-D. When the supply of D-2 is limited, e.g., 0.1 L in this study, the presence Of (SO2)-O-18 suppresses the NO-D reaction. With a sufficient supply of D-2, e.g., 0.4 L and higher, D-atom competing reactions do not play a role any more because the reactions of both NO and (SO2)-O-18 with D proceed only to a very limited extent. As such, generation of O atoms from (SO2)-O-18 dissociation is the main reaction that leads to the suppression in NO dissociation and consequently, N-2 production.
It is also concluded that the presence of (SO2)-O-18 does not seriously poison the active sites on the Pt surface, providing that there is a sufficient D supply to remove O atoms from both NO dissociation and (SO2)-O-18 dissociation.

• 出版日期2009-9-1