TY - JOUR

T1 - Oxygen reduction on structurally well defined, bimetallic PtRu surfaces

T2 - monolayer PtxRu1-x/Ru(0001) surface alloys versus Pt film covered Ru(0001)

AU - Brimaud, S.

AU - Engstfeld, A. K.

AU - Alves, O. B.

AU - Hoster, H. E.

AU - Behm, R. J.

PY - 2014/2

Y1 - 2014/2

N2 - The electrocatalytic activity of different, structurally well defined bimetallic PtRu surfaces in the oxygen reduction reaction was investigated by a combination of scanning tunnelling microscopy and electrochemical measurements performed under controlled mass transport conditions in a flow cell. We compare the effect of pseudomorphic Pt cover layers, mimicking the situation in a core-shell Pt/Ru nanoparticle, and of mixed PtxRu1-x monolayer surface alloys, reflecting the situation in an alloyed nanoparticle. The results unambiguously demonstrate that these bimetallic surfaces can reach activities well in excess of that of Pt(111), both for the film surfaces and the surface alloys, by optimizing the Pt surface content (surface alloys) or the Pt film thickness (film surfaces). The results are compared with simulated kinetic current-potential profiles based on existent density functional theory calculations (Greeley and Norskov, J Phys Chem C 113:4932, 2009; Lischka et al., Electrochim Acta 52:2219, 2007) revealing very good agreement in trends. Potential and limits of this approach are discussed.

AB - The electrocatalytic activity of different, structurally well defined bimetallic PtRu surfaces in the oxygen reduction reaction was investigated by a combination of scanning tunnelling microscopy and electrochemical measurements performed under controlled mass transport conditions in a flow cell. We compare the effect of pseudomorphic Pt cover layers, mimicking the situation in a core-shell Pt/Ru nanoparticle, and of mixed PtxRu1-x monolayer surface alloys, reflecting the situation in an alloyed nanoparticle. The results unambiguously demonstrate that these bimetallic surfaces can reach activities well in excess of that of Pt(111), both for the film surfaces and the surface alloys, by optimizing the Pt surface content (surface alloys) or the Pt film thickness (film surfaces). The results are compared with simulated kinetic current-potential profiles based on existent density functional theory calculations (Greeley and Norskov, J Phys Chem C 113:4932, 2009; Lischka et al., Electrochim Acta 52:2219, 2007) revealing very good agreement in trends. Potential and limits of this approach are discussed.

KW - Bimetallic surface

KW - Surface alloy

KW - Platinum monolayer

KW - Electrocatalysis

KW - Oxygen reduction reaction

KW - Scanning probe microscopy

KW - RUTHENIUM AD-ATOMS

KW - HETEROGENEOUS CATALYSIS

KW - ELECTRONIC-PROPERTIES

KW - AMMONIA-SYNTHESIS

KW - CARBON-MONOXIDE

KW - SINGLE-CRYSTAL

KW - METAL-SURFACES

KW - CO ADSORPTION

KW - PLATINUM

KW - ELECTROCATALYSTS

U2 - 10.1007/s11244-013-0177-0

DO - 10.1007/s11244-013-0177-0

M3 - Journal article

VL - 57

SP - 222

EP - 235

JO - Topics in Catalysis

JF - Topics in Catalysis

SN - 1022-5528

IS - 1-4

ER -