Adsorption and reaction of maleic anhydride on Mo(110), monolayer Pd(111)/Mo(110), and multilayer Pd(111)/Mo(110)

Journal Article · Wed Apr 03 04:00:00 EST 1996 · Langmuir

DOI:https://doi.org/10.1021/la950290a· OSTI ID:232530

Xu, C; Goodman, D W ^[1]

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1. Texas A&M Univ., College Station, TX (United States)

The adsorption and reaction of maleic anhydride and deuterated maleic anhydride on Mo(110), monolayer Pd/Mo(110), and multilayer Pd(111)/Mo(110) surfaces have been studied using temperature-programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS). Maleic anhydride adsorbs irreversibly on the Mo(110) surface at 100 K. Heating to 1200 K yields adsorbed carbon (C{sub ads}) and gas-phase CO and H{sub 2}. In contrast, the adsorption of maleic anhydride on monolayer Pd(111)/Mo(110) and multilayer Pd(111)/Mo(110) surfaces is largely reversible with the chemisorbed maleic anhydride desorbing at 365 and 375 K, respectively. Approximately 15% of the chemisorbed maleic anhydride decomposes upon heating to 400K, forming CO, CO{sub 2} and C{sub 2}H{sub 2}; C{sub 2}H{sub 2} further dehydrogenates upon heating to C{sub ads} and gas-phase H{sub 2}. The HREELS measurements indicate that maleic anhydride is bonded to multilayer Pd(111)/Mo(110) through the olefin bond in a di-{sigma} configuration, while on monolayer Pd(111)/Mo(110), the maleic anhydride is bonded to the surface through the olefin via a {pi}-bond. On the Mo(110) surface, maleic anhydride is bonded to the surface through the ring oxygen with the molecular plane perpendicular to the surface. As a result of this modified adsorption geometry, the carbonyl stretching mode is red-shifted nearly 150 cm{sup -1} on the monolayer Pd(111)/Mo(110) surface, unshifted on the multilayer Pd(111)/Mo(110) surface, and blue-shifted by nearly 100 cm{sup -1} on the Mo(110) surface. 31 refs., 14 figs., 3 tabs.

• OSTI ID: 232530
• Journal Information: Langmuir, Journal Name: Langmuir Journal Issue: 7 Vol. 12; ISSN LANGD5; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ADSORPTION
BIMETALS
CATALYSTS
CHEMICAL BONDS
CHEMICAL REACTIONS
ENERGY SPECTRA
MALEIC ACID
MASS SPECTRA
MOLYBDENUM
ORGANIC COMPOUNDS
PALLADIUM
THIN FILMS