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The kinetics of oxygen reduction is studied in acid solutions on Pt monolayers deposited on a Pd(111) surface and on carbon-supported Pd nanoparticles using the rotating disk-ring electrode technique. A small but significant enhancement with Pt monolayers on Pd(111) and Pd nanoparticle surfaces in comparison with the reaction on Pt(111) and Pt nanoparticles is observed by the kinetics of O2 reduction.

Ethanol, with its high energy density, likely production from renewable sources and ease of storage and transportation, is almost the ideal combustible for fuel cells wherein its chemical energy can be converted directly into electrical energy. However, commercialization of direct ethanol fuel cells has been impeded by ethanol’s slow, inefficient oxidation even at the best electrocatalysts. We synthesized a ternary PtRhSnO2/C electrocatalyst by depositing platinum and rhodium atoms on carbon-supported tin dioxide nanoparticles that is capable of oxidizing ethanol with high efficiency and holds great promise for resolving the impediments to developing practical direct ethanol fuel cells. This electrocatalyst effectively splits the C–C bond in ethanol at room temperature in acid solutions, facilitating its oxidation at low potentials to CO2, which has not been achieved with existing catalysts. Our experiments and density functional theory calculations indicate that the electrocatalyst’s activity is due to the specific property of each of its constituents, induced by their interactions. These findings help explain the high activity of Pt–Ru for methanol oxidation and the lack of it for ethanol oxidation, and point to the way to accomplishing the C–C bond splitting in other catalytic processes. [ABSTRACT FROM AUTHOR]

Core nanoparticles of Pd, Pd-Ru, and Pd supported on an amorphous carbon are deposited, by a flame-based process, onto glassy carbon rotating disk electrodes and gas diffusion layers. A Pt monolayer was deposited using galvanic displacement of an underpotentially deposited Cu monolayer with Pt. The Pt monolayer is then tested to determine the electrochemical surface area and activity toward the oxygen reduction reaction. Depositions of the Pd core were applied at substrate temperatures of 250°C and 150°C. A PtML/Pd(250°C) has higher Pt mass and specific ORR activities than PtML/Pd(150°C). This is due to smoother surface of Pd (250°C) compared to Pd (150°C). During membrane electrode assembly testing in O2, the Pt mass activity was 0.532 A/mgPt at 0.9V. The voltage at 1 A/cm2 was 0.613V, and a peak power density of 0.93W/cm2 was achieved. [ABSTRACT FROM AUTHOR]

Ethanol, with its high energy density, likely production from renewable sources and ease of storage and transportation, is almost the ideal combustible for fuel cells wherein its chemical energy can be converted directly into electrical energy. However, commercialization of direct ethanol fuel cells has been impeded by ethanol’s slow, inefficient oxidation even at the best electrocatalysts. We synthesized a ternary PtRhSnO2/C electrocatalyst by depositing platinum and rhodium atoms on carbon-supported tin dioxide nanoparticles that is capable of oxidizing ethanol with high efficiency and holds great promise for resolving the impediments to developing practical direct ethanol fuel cells. This electrocatalyst effectively splits the C–C bond in ethanol at room temperature in acid solutions, facilitating its oxidation at low potentials to CO2, which has not been achieved with existing catalysts. Our experiments and density functional theory calculations indicate that the electrocatalyst’s activity is due to the specific property of each of its constituents, induced by their interactions. These findings help explain the high activity of Pt–Ru for methanol oxidation and the lack of it for ethanol oxidation, and point to the way to accomplishing the C–C bond splitting in other catalytic processes. [ABSTRACT FROM AUTHOR]