PT-ACID SOLUTION(CU AND PD+CU ALLOY PARTICLES FORMED IN THE UNDERPOTENTIAL DEPOSITION REGION OF CU2+ IN PERCHLORIC)

Formation of Pt + Cu and Pd + Cu alloy particles in acidic solutions a t deposition electrode potentials which were located in the underpoten tial deposition region (upd) of Cu2+ ion was investigated by transmiss ion electron microscopy (TEM). It was found that the behavior of the f raction of Cu in the alloy particles is similar to that of the Au-Cu a lloy particles, that is, the fraction of Cu is independent of concentr ation of Cu2+ ion in solution but is dependent of deposition potential in the upd region of Cu2+ ion. This correlation can be described by a n experimental formula. Unlike the case of the Au + Cu alloy particles , we did not find the multiply twinned particles (MTPs) of Pt + Cu all oy particles. The MTPs of Pd + Cu alloy particles were observed. Howev er, these MTPs were not stable and changed to polycrystalline material quickly during the observation by TEM. Ag + Cu alloy particles were n ot formed in the upd region of Cu2+ ion. (C) 1998 Published by Elsevie r Science Ltd. All rights reserved.