Methanol electrooxidation on well-characterized Pt-Ru alloys

Journal Article · Thu Nov 18 04:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100148a030· OSTI ID:5651666

Gasteiger, H A; Markovic, N; Ross, Jr, P N; Cairns, E J ^[1]

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1. Univ. of California, Berkeley, CA (United States) Lawrence Berkeley Lab., CA (United States)

The catalytic activity of single-phase polycrystalline Pt-Ru bulk alloys toward the electrooxidation of methanol in sulfuric acid electrolyte at room temperature was measured for the first time on well-characterized alloy surfaces, in terms of surface composition and true surface area. Sputter-cleaned and annealed alloys were prepared in ultrahigh vacuum (UHV) and the surface composition of oxygen-free surfaces was assessed via low-energy ion scattering (LEIS). Pt-Ru alloy surfaces annealed in UHV were strongly enriched in Pt, whereas the surface composition of sputter-cleaned alloys was essentially identical to their bulk composition. It was shown that the sputter-cleaned alloy with a Ru surface of [approx equal] 10 atomic % gave the highest catalytic enhancement (over pure Pt) for the steady-state electrooxidation of methanol at 25[degree]C and 0.5 V, viz., by a factor of 12 in 5.0 mM CH[sub 3]OH solution and by a factor of 30 in 0.5 M CH[sub 3]OH. It was found that the balance between the rate of methanol adsorption and the rate of the oxidative removal of dehydrogenated fragments determines the activities of Pt-Ru alloys with different Ru surface compositions. 51 refs., 9 figs., 2 tabs.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5651666
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:46; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400400 -- Electrochemistry
ALCOHOLS
ALLOYS
ANNEALING
CATALYSIS
CHEMICAL REACTIONS
ELECTROLYSIS
HEAT TREATMENTS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INORGANIC ACIDS
LYSIS
METHANOL
ORGANIC COMPOUNDS
OXIDATION
PLATINUM ALLOYS
PLATINUM METAL ALLOYS
RUTHENIUM ALLOYS
SPUTTERING
SULFURIC ACID
SURFACE PROPERTIES
ULTRAHIGH VACUUM
VOLTAMETRY