Direct Visualization of Catalytically Active Sites at the FeO-Pt(111) Interface

TY - JOUR

T1 - Direct Visualization of Catalytically Active Sites at the FeO-Pt(111) Interface

AU - Kudernatsch, Wilhelmine

AU - Peng, Guowen

AU - Zeuthen, Helene

AU - Bai, Yunhai

AU - Merte, Richard Lindsay

AU - Lammich, Lutz

AU - Besenbacher, Flemming

AU - Mavrikakis, Manos

AU - Wendt, Stefan

PY - 2015

Y1 - 2015

N2 - Within the area of surface science one of the “Holy Grails” is to directly visualize a chemical reaction at the atomic scale. Whereas this goal has been reached by high-resolution scanning tunneling microscopy (STM) in a number of cases for reactions occurring at flat surfaces, such a direct view is often inhibited for reaction occurring at steps and interfaces. Here we have studied the CO oxidation reaction at the interface between ultrathin FeO islands and a Pt(111) support by in-situ STM and density functional theory (DFT) calculations. Time-lapsed STM imaging on this inverse model catalyst in O2 and CO environments revealed catalytic activity occurring at the FeO–Pt(111) interface and directly showed that the Fe-edges host the catalytically most active sites for the CO oxidation reaction. This is an important result since previous evidence for the catalytic activity of the FeO–Pt(111) interface is essentially based on averaging techniques in conjunction with DFT calculations. The presented STM results are in accord with DFT+U calculations, in which we compare possible CO oxidation pathways on oxidized Fe-edges and O-edges. We found that the CO oxidation reaction is more favorable on the oxidized Fe-edges, both thermodynamically and kinetically.

AB - Within the area of surface science one of the “Holy Grails” is to directly visualize a chemical reaction at the atomic scale. Whereas this goal has been reached by high-resolution scanning tunneling microscopy (STM) in a number of cases for reactions occurring at flat surfaces, such a direct view is often inhibited for reaction occurring at steps and interfaces. Here we have studied the CO oxidation reaction at the interface between ultrathin FeO islands and a Pt(111) support by in-situ STM and density functional theory (DFT) calculations. Time-lapsed STM imaging on this inverse model catalyst in O2 and CO environments revealed catalytic activity occurring at the FeO–Pt(111) interface and directly showed that the Fe-edges host the catalytically most active sites for the CO oxidation reaction. This is an important result since previous evidence for the catalytic activity of the FeO–Pt(111) interface is essentially based on averaging techniques in conjunction with DFT calculations. The presented STM results are in accord with DFT+U calculations, in which we compare possible CO oxidation pathways on oxidized Fe-edges and O-edges. We found that the CO oxidation reaction is more favorable on the oxidized Fe-edges, both thermodynamically and kinetically.

KW - catalysis

KW - active sites

KW - CO oxidation

KW - FeO islands

KW - Pt

KW - in-situ scanning tunneling microscopy (STM)

KW - density functional theory (DFT)

U2 - 10.1021/acsnano.5b02339

DO - 10.1021/acsnano.5b02339

M3 - Journal article

C2 - 26027877

SN - 1936-0851

VL - 9

SP - 7804

EP - 7814

JO - ACS Nano

JF - ACS Nano

IS - 8

ER -