Underpotential deposition and involved alloy formation of cadmium on silver particles modified HOPG substrates

RUBÉN E. AMBRUSI; MARÍA E. PRONSATO; SILVANA G. GARCÍA

JOURNAL OF SOLID STATE ELECTROCHEMISTRY (PRINT)

SPRINGER

Año: 2018

1432-8488

Cadmium underpotential deposition (UPD) on Ag particles modified highly orderedpyrolytic graphite (HOPG) surfaces, and the involved alloy formation, werestudied by conventional electrochemical techniques. Voltammetric resultsindicated that the Cd UPD followed an adsorption behavior different from thatobserved for massive Ag electrodes and Ag particles supported on vitreouscarbon. Nanometer-sized bimetallic Cd-Ag particles were characterized byex-situ atomic force microscopy (AFM). Initially, AFM images show Ag depositsof similar size distributed preferably on HOPG step edges. No remarkablemorphological changes are observed on the surface after the subsequent Cddeposition, suggesting that the Cd particles are deposited selectively over theAg crystals. From the analysis of desorption spectra, employing differentpolarization times, and Density Functional Theory (DFT) calculations, the formationof a Cd-Ag surface alloy could be inferred.