Catalytic Activity of Platinum Monolayer on Iridium and Rhenium Alloy Nanoparticles for the Oxygen Reduction Reaction

Journal Article · Fri May 04 04:00:00 EDT 2012 · ACS Catalysis

DOI:https://doi.org/10.1021/cs200592x· OSTI ID:1053344

Karan, Hiroko I.; Sasaki, Kotaro; Kuttiyiel, Kurian; Farberow, Carrie A.; Mavrikakis, Manos; Adzic, Radoslav R.

A new type of electrocatalyst with a core–shell structure that consists of a platinum monolayer shell placed on an iridium–rhenium nanoparticle core or platinum and palladium bilayer shell deposited on that core has been prepared and tested for electrocatalytic activity for the oxygen reduction reaction. Carbon-supported iridium–rhenium alloy nanoparticles with several different molar ratios of Ir to Re were prepared by reducing metal chlorides dispersed on Vulcan carbon with hydrogen gas at 400 °C for 1 h. These catalysts showed specific electrocatalytic activity for oxygen reduction reaction comparable to that of platinum. The activities of Pt_ML/Pd_ML/Ir₂Re₁, Pt_ML/Pd_2layers/Ir₂Re₁, and Pt_ML/Pd_2layers/Ir₇Re₃ catalysts were, in fact, better than that of conventional platinum electrocatalysts, and their mass activities exceeded the 2015 DOE target. Our density functional theory calculations revealed that the molar ratio of Ir to Re affects the binding strength of adsorbed OH and, thereby, the O₂ reduction activity of the catalysts. The maximum specific activity was found for an intermediate OH binding energy with the corresponding catalyst on the top of the volcano plot. The monolayer concept facilitates the use of much less platinum than in other approaches. Finally, the results with the Pt_ML/Pd_ML/Ir₂Re electrocatalyst indicate that it is a promising alternative to conventional Pt electrocatalysts in low-temperature fuel cells.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: DOE Office of Science; USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1053344
• Journal Information: ACS Catalysis, Journal Name: ACS Catalysis Journal Issue: 5 Vol. 2; ISSN 2155-5435
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory