Underpotential Co-Deposition of Cu_subscript(1-x)Pt_subscript(x) Alloys
J Mallett, Ugo Bertocci, Erik B. Svedberg, John E. Bonevich, Alexander J. Shapiro, William F. Egelhoff Jr., Thomas P. Moffat
The electrodeposition of Cu_subscript (1-x)Pt_subscript(x) alloys by underpotential co-deposition of Cu with Pt is demonstrated using an H_subscript(2)SO_subscript(4)-CuSO_subscript(4-)PtCl_subscript(4)_superscript(2-) electrolyte. The composition and structure of 1 microns thick alloy films grown at different potentials were examined by EDS, XRD and TEM. A thermodynamic rational for the alloying process is provided bu a symmetrical regular solution model whereby underpotential co-deposition of Cu is ascribed to the negative enthalpy of mixing with Pt. The observed dependence of alloy composition on potential is in good agreement with equiatomic mixing enthalpy of -18 kJ/mol, obtained from calculations by Miedema et al. An EQCM was used to provide a time resolved assessment of the alloy formation process. Simultaneous measurement of the mass and current transients during potential steps enable the effects of submonolayer underpotential deposition of Cu onto a Pt rich surface to be observed and separated from the subsequent steady-state co-deposition of Cu with Pt.
ECS Meeting | 209th | | ECS
May 7-12, 2006
ECS Meeting Proceedings
co-deposition, electrodeposition, underpotential
, Bertocci, U.
, Svedberg, E.
, Bonevich, J.
, Shapiro, A.
, Egelhoff, W.
and Moffat, T.
Underpotential Co-Deposition of Cu_subscript(1-x)Pt_subscript(x) Alloys, ECS Meeting | 209th | | ECS
(Accessed December 11, 2023)