N 2 Product Internal-State Distributions for the Steady-State Reactions of NO with H 2 and NH 3 on the Pt(100) Surface †

The Journal of Physical Chemistry B (Impact Factor: 3.38). 09/2001; 105(37):8725-8728. DOI: 10.1021/jp0108216
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    ABSTRACT: The interaction between NO and CH3OH on the surface of stepped Pt(332) was investigated using Fourier transform infra red reflection–absorption spectroscopy (FTIR-RAS) and thermal desorption spectroscopy (TDS). At 90K, pre-dosed CH3OH molecules preferentially adsorb on step sites, suppressing the adsorption of NO molecules on the same sites. However, due to a much stronger interaction with Pt, at 150K and higher, the adsorption of NO molecules on step sites is restored, giving rise to peaks closely resembling those of NO molecules adsorbed on clean Pt(332) surface. Adsorbed CH3OH is very reactive on this surface, and is readily oxidized to formate in the presence of O2, even at 150K. In contrast, reactions between CH3OH and co-adsorbed NO are slight to non-existent. There are no new peaks in association with intermediates resulting from CH3OH–NO interactions. It is concluded that the reduction of NO with CH3OH on Pt(332) does not proceed through a mechanism of forming intermediates.
    Surface Science 06/2007; 601(12):2467-2472. DOI:10.1016/j.susc.2007.04.046 · 1.87 Impact Factor
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    ABSTRACT: Interactions between S18O2 and NO on the surface of stepped Pt(3 3 2) were studied using Fourier transform infra red reflection-absorption spectroscopy (FTIR-RAS) combined with thermal desorption spectroscopy (TDS). Adsorbed S18O2 does not seem to have a preference for step sites on Pt(3 3 2). As such, the presence of S18O2 molecules following exposures of ⩽1.6 L does not significantly block the subsequent adsorption of NO (⩽0.8 L) on these step sites. Adsorbed S18O2 molecules undergo dissociation (S18O2(a) → S18O(a) + 18O(a)) as the surface temperature is increased to 250 K and above, but the resultant 18O(a) further reacts with sulfur oxides (S18O2(a) and S18O(a)) to form S18Ox (x > 2) species at ∼400 K and above. The S18Ox species desorb as S18O2. Even though the presence of co-adsorbed S18O2 suppresses NO dissociation and subsequent N2 production, this effect is not significantly enhanced with increasing the exposures of S18O2 in the range ⩽1.6 L; N2 desorption is still detectable at an exposure of 1.6 L S18O2, at which a considerable amount of S18O2 desorption is detected.
    Surface Science 01/2009; 603(2):336–340. DOI:10.1016/j.susc.2008.11.018 · 1.87 Impact Factor
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    ABSTRACT: Selective catalytic reduction (SCR) of NOx is one of the important strategies in regulating NOx emissions. In the past several decades, the reactions of NOx (mainly NO) with H2, CO, NH3 and hydrocarbons have been extensively investigated under ambient conditions and have been summarized in numerous reviews. Nonetheless, many questions appear to be difficult to answer under ambient conditions, e.g., the pathways through which the reactions proceed. The introduction and development of modern surface science technology has played an indispensable role and is widely employed in the studies of the SCR of NOx, greatly helping to elucidate the mechanisms of the reactions with CO, H2, and NH3. However, so far, there are few review papers systematically summarizing the progress of such studies.Recently, systematic surface science studies have been conducted on the mechanisms of SCR of NO with organic molecules including ethylene, benzene, and ethanol, which are much more complicated than those with H2, CO and NH3 and have drawn much less attention before. It is confirmed that these reactions can be reliably and most importantly, reproducibly probed by surface science technology, but a great deal of work remains to be done.Since Delmon et al. have provided a very thorough review of the researches on catalytic removal of NO (reactions with H2, CO and NH3) up to 1998, in which the reactions conducted both under ambient and UHV conditions were included, this review mainly concentrates on the progress made since 1998.
    Surface Science 06/2009; 603(10-12-603):1740-1750. DOI:10.1016/j.susc.2008.09.051 · 1.87 Impact Factor


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May 21, 2014