Structure and reactivity of surface oxides on Pt(110) during catalytic CO oxidation

• Published in: Physical review letters Vol. 95; no. 25; pp. 255505.1 - 255505.4
• Main Authors: ACKERMANN, M. D, PEDERSEN, T. M, FRENKEN, J. W. M, HENDRIKSEN, B. L. M, ROBACH, O, BOBARU, S. C, POPA, I, QUIROS, C, KIM, H, HAMMER, B, FERRER, S
• Format: Journal Article
• Language: English
• Published: Ridge, NY American Physical Society 16-12-2005
• Subjects: CARBON MONOXIDE; CARBONATES; CATALYSIS; CATALYSTS; Condensed matter: structure, mechanical and thermal properties; DENSITY FUNCTIONAL METHOD; Exact sciences and technology; MATERIALS SCIENCE; OXIDATION; Physics; PLATINUM; PRESSURE RANGE KILO PA; REACTIVITY; Solid surfaces and solid-solid interfaces; SURFACES; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); TEMPERATURE RANGE 0400-1000 K; X-RAY DIFFRACTION; Surface termination; Platinum; Transition elements; Oxidation; Carbon monoxide; XRD; High temperature; Catalyst activity; High pressure; Surface structure
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.95.255505

We present the first structure determination by surface x-ray diffraction during the restructuring of a model catalyst under reaction conditions, i.e., at high pressure and high temperature, and correlate the restructuring with a change in catalytic activity. We have analyzed the Pt(110) surface during CO oxidation at pressures up to 0.5 bar and temperatures up to 625 K. Depending on the pressure ratio, we find three well-defined structures: namely, (i) the bulk-terminated Pt(110) surface, (ii) a thin, commensurate oxide, and (iii) a thin, incommensurate oxide. The commensurate oxide only appears under reaction conditions, i.e., when both and CO are present and at sufficiently high temperatures. Density functional theory calculations indicate that the commensurate oxide is stabilized by carbonate ions (CO3(2-)). Both oxides have a substantially higher catalytic activity than the bulk-terminated Pt surface.