TPD study of the adsorption and reaction of nitromethane and methyl nitrite on ordered Pt-Sn surface alloys

J. W. Peck; D. I. Mahon; D. E. Beck; Bruce E. Koel

doi:10.1016/S0039-6028(98)00198-8

TPD study of the adsorption and reaction of nitromethane and methyl nitrite on ordered Pt-Sn surface alloys

J. W. Peck, D. I. Mahon, D. E. Beck, Bruce E. Koel

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Abstract

The adsorption and reaction of the isomers nitromethane (CH₃NO₂) and methyl nitrite (CH₃ONO) on two ordered Sn/Pt(111) surface alloys were studied using TPD, AES, and LEED. Even though the Sn-O bond is stronger than the Pt-O bond and Sn is more easily oxidized than Pt, alloying with Sn reduces the reactivity of the Pt(111) surface for both of these oxygen-containing molecules. This is because of kinetic limitations due to a weaker chemisorption bond and an increased activation energy for dissociation for these molecules on the alloys compared to Pt(111). Nitromethane only weakly adsorbs on the Sn/Pt(111) surface alloys, shows no thermal reaction during TPD, and undergoes completely reversible adsorption under UHV conditions. Methyl nitrite is a much more reactive molecule due to the weak CH₃O-NO bond, and most of the chemisorbed methyl nitrite decomposes below 240K on the alloy surfaces to produce NO and a methoxy species. Surface methoxy is a stable intermediate until ∼300K on the alloys, and then it dehydrogenates to evolve gas phase formaldehyde with high selectivity against complete dehydrogenation to form CO on both alloy surfaces.

Original language	English (US)
Pages (from-to)	170-188
Number of pages	19
Journal	Surface Science
Volume	410
Issue number	2-3
DOIs	https://doi.org/10.1016/S0039-6028(98)00198-8
State	Published - Aug 1 1998

All Science Journal Classification (ASJC) codes

Condensed Matter Physics
Surfaces and Interfaces
Surfaces, Coatings and Films
Materials Chemistry

Keywords

Alloys
Auger electron spectroscopy (AES)
Chemisorption
Low energy electron diffraction (LEED)
Low index single crystal surfaces
Methylnitrite
Nitromethane
Platinum
Thermal desorption spectroscopy
Tin

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10.1016/S0039-6028(98)00198-8

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title = "TPD study of the adsorption and reaction of nitromethane and methyl nitrite on ordered Pt-Sn surface alloys",

abstract = "The adsorption and reaction of the isomers nitromethane (CH3NO2) and methyl nitrite (CH3ONO) on two ordered Sn/Pt(111) surface alloys were studied using TPD, AES, and LEED. Even though the Sn-O bond is stronger than the Pt-O bond and Sn is more easily oxidized than Pt, alloying with Sn reduces the reactivity of the Pt(111) surface for both of these oxygen-containing molecules. This is because of kinetic limitations due to a weaker chemisorption bond and an increased activation energy for dissociation for these molecules on the alloys compared to Pt(111). Nitromethane only weakly adsorbs on the Sn/Pt(111) surface alloys, shows no thermal reaction during TPD, and undergoes completely reversible adsorption under UHV conditions. Methyl nitrite is a much more reactive molecule due to the weak CH3O-NO bond, and most of the chemisorbed methyl nitrite decomposes below 240K on the alloy surfaces to produce NO and a methoxy species. Surface methoxy is a stable intermediate until ∼300K on the alloys, and then it dehydrogenates to evolve gas phase formaldehyde with high selectivity against complete dehydrogenation to form CO on both alloy surfaces.",

keywords = "Alloys, Auger electron spectroscopy (AES), Chemisorption, Low energy electron diffraction (LEED), Low index single crystal surfaces, Methylnitrite, Nitromethane, Platinum, Thermal desorption spectroscopy, Tin",

author = "Peck, {J. W.} and Mahon, {D. I.} and Beck, {D. E.} and Koel, {Bruce E.}",

note = "Funding Information: This work was partially supported by the Department of Energy, Office of Basic Energy Sciences, Chemical Division and the Army Research Office. The authors would like to thank J. Wang for synthesizing the methyl nitrite sample and J.M. White for making his results available to us prior to their publication. J.W.P. gratefully thanks the Department of Education for a graduate research fellowship.",

year = "1998",

month = aug,

day = "1",

doi = "10.1016/S0039-6028(98)00198-8",

language = "English (US)",

volume = "410",

pages = "170--188",

journal = "Surface Science",

issn = "0039-6028",

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number = "2-3",

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T1 - TPD study of the adsorption and reaction of nitromethane and methyl nitrite on ordered Pt-Sn surface alloys

AU - Peck, J. W.

AU - Mahon, D. I.

AU - Beck, D. E.

AU - Koel, Bruce E.

N1 - Funding Information: This work was partially supported by the Department of Energy, Office of Basic Energy Sciences, Chemical Division and the Army Research Office. The authors would like to thank J. Wang for synthesizing the methyl nitrite sample and J.M. White for making his results available to us prior to their publication. J.W.P. gratefully thanks the Department of Education for a graduate research fellowship.

PY - 1998/8/1

Y1 - 1998/8/1

N2 - The adsorption and reaction of the isomers nitromethane (CH3NO2) and methyl nitrite (CH3ONO) on two ordered Sn/Pt(111) surface alloys were studied using TPD, AES, and LEED. Even though the Sn-O bond is stronger than the Pt-O bond and Sn is more easily oxidized than Pt, alloying with Sn reduces the reactivity of the Pt(111) surface for both of these oxygen-containing molecules. This is because of kinetic limitations due to a weaker chemisorption bond and an increased activation energy for dissociation for these molecules on the alloys compared to Pt(111). Nitromethane only weakly adsorbs on the Sn/Pt(111) surface alloys, shows no thermal reaction during TPD, and undergoes completely reversible adsorption under UHV conditions. Methyl nitrite is a much more reactive molecule due to the weak CH3O-NO bond, and most of the chemisorbed methyl nitrite decomposes below 240K on the alloy surfaces to produce NO and a methoxy species. Surface methoxy is a stable intermediate until ∼300K on the alloys, and then it dehydrogenates to evolve gas phase formaldehyde with high selectivity against complete dehydrogenation to form CO on both alloy surfaces.

AB - The adsorption and reaction of the isomers nitromethane (CH3NO2) and methyl nitrite (CH3ONO) on two ordered Sn/Pt(111) surface alloys were studied using TPD, AES, and LEED. Even though the Sn-O bond is stronger than the Pt-O bond and Sn is more easily oxidized than Pt, alloying with Sn reduces the reactivity of the Pt(111) surface for both of these oxygen-containing molecules. This is because of kinetic limitations due to a weaker chemisorption bond and an increased activation energy for dissociation for these molecules on the alloys compared to Pt(111). Nitromethane only weakly adsorbs on the Sn/Pt(111) surface alloys, shows no thermal reaction during TPD, and undergoes completely reversible adsorption under UHV conditions. Methyl nitrite is a much more reactive molecule due to the weak CH3O-NO bond, and most of the chemisorbed methyl nitrite decomposes below 240K on the alloy surfaces to produce NO and a methoxy species. Surface methoxy is a stable intermediate until ∼300K on the alloys, and then it dehydrogenates to evolve gas phase formaldehyde with high selectivity against complete dehydrogenation to form CO on both alloy surfaces.

KW - Alloys

KW - Auger electron spectroscopy (AES)

KW - Chemisorption

KW - Low energy electron diffraction (LEED)

KW - Low index single crystal surfaces

KW - Methylnitrite

KW - Nitromethane

KW - Platinum

KW - Thermal desorption spectroscopy

KW - Tin

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U2 - 10.1016/S0039-6028(98)00198-8

DO - 10.1016/S0039-6028(98)00198-8

M3 - Article

AN - SCOPUS:0032142407

SN - 0039-6028

VL - 410

SP - 170

EP - 188

JO - Surface Science

JF - Surface Science

IS - 2-3

ER -

TPD study of the adsorption and reaction of nitromethane and methyl nitrite on ordered Pt-Sn surface alloys

Abstract

All Science Journal Classification (ASJC) codes

Keywords

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