Eur. Phys. J. D 24, 253-256 (2003)
https://doi.org/10.1140/epjd/e2003-00110-1

EXAFS and optical spectroscopy characterisation of reduction products of binary silver-copper ion mixture in mordenite

¹ Department of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
² European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble Cedex, France
³ Centro de Ciencias de la Materia Condensada UNAM, 22800 Ensenada, B.C., Mexico

Corresponding author: ^a S.G.Fiddy@soton.ac.uk

Received: 10 September 2002
Published online: 3 July 2003

Abstract

Ag⁺, Cu²⁺ and Ag binary mixtures with different Ag/Cu ratios were supported on mordenite with Si/Al ratio equal to 10 and reduced in the temperature range  K. Diffuse Reflectance UV-Visible spectra reveal appearance of Ag₈ clusters and small copper metal particles. Cu K-edge EXAFS show for Cu-rich non-reduced samples the presence of only oxygen shell; but for the Ag-rich sample, the presence of heavier backscatterer is also indicated producing a different EXAFS envelope. Silver EXAFS analysis suggests that, for the reduced samples, there are both and distances ( and coordination numbers of approx 2 and of 1.3 respectively for the :1 and 1:3 samples). Importantly, for the reduced sample, the EXAFS indicates that Ag appears to promote/stabilise Cu cluster formation whereas Cu appears to impede/destabilise Ag cluster formation.