Dl. Lu et K. Tanaka, MECHANISM FOR THE FORMATION OF AU-CU ALLOY MULTIPLY TWINNED PARTICLESFORMED IN THE REGION OF UPD OF CU2-ACID SOLUTION( IN PERCHLORIC), Surface science, 409(2), 1998, pp. 283-289
Au-Cu alloy icosahedral and decahedral particles (multiply twinned par
ticles) are formed by codeposition of Au and Cu ions on the carbon ele
ctrode at positive potentials which are located in the region of under
potential deposition (UPD) of Cu2+ on the Au electrode, where only Au
fee single crystal particles grow but neither decahedral particles nor
icosahedral particles of pure Au are Formed. It is suggested that due
to the adsorption of Cu+ on the surface of Au overlayer of the alloy
particles, the surface electron density increases. For a stable surfac
e state the surface atoms are contracted. This is similar to the recon
struction occurring on the Au(111) electrode surface at negative poten
tials. Due to the contraction of the surface atoms, there is a possibi
lity of the formation of the Au-Cu alloy icosahedral and decahedral pa
rticles. It is supposed that the growth mode of the Au-Cu alloy partic
les formed in solution in the region of UPD of Cu2+ is a layer-by-laye
r growth. (C) 1998 Elsevier Science B.V. All rights reserved.