Underpotential Deposition of Cu on Pt(100): Effects of Anions onAdsorption Isotherms and Interface Structures

Journal Article · Wed Oct 15 04:00:00 EDT 1997 · Electrochimica Acta

OSTI ID:901652

Markovic, N M; Grgur, B N; Lucas, C A; Ross, Jr, P N

The results presented in this study show definitely thatcopper deposition in perchloric acid is a very slow, kineticallycontrolled process. In nearly halide free supporting electrolytes duappeared to be deposited at underpotential in metallic islands (or'patches') having the platinum lattice constant. The presence of Br-anions significantly enhances the kinetics of the Cu UPD on the Pt(100)electrode. The total amount of Cu deposited at underpotential is ca. 1 ML(1 ML = 1 Cu adatom per Pt atom). The results obtained from the surfaceX-ray diffraction measurements showed the formation of an orderedstructure of Pr into a c(2 x 2) unit cell on the top of a p(1 x 1)pseudomorphic layer of Cu. In a solution free of Cu no ordered structureof Pr has been found on Pt(100). RRDE and SXS results indicate beyond anydoubt that the surface coverage by Br undergoes only negligible changesupon the deposition of Cu even up to a nominal monolayer. We propose,therefore, that the mechanism of Cu UPD occurs by displacement of bromineadatoms from the Pt surface by Cu adatoms through a 'turn-over' processin which Cu is sandwiched between the Pt surface and the Brad overlayer,i.e., a Pt(100)-Cu-Br bi-layer structure.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Energy Research
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 901652
• Report Number(s): LBNL--41109
• Journal Information: Electrochimica Acta, Journal Name: Electrochimica Acta Journal Issue: 6-7 Vol. 44; ISSN 0013-4686; ISSN ELCAAV
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ADSORPTION ISOTHERMS
BROMIDES
CATALYTIC EFFECTS
COPPER
DEPOSITION
PERCHLORIC ACID
PLATINUM
SUBSTRATES
X-RAY DIFFRACTION