Abnormal infrared effects and electrocatalytic properties of nanometer scale thin film of PtRu alloys for CO adsorption and oxidation

Nanometer scale thin films of PtRu alloy supported on glassy carbon (nm-PtR u/GC) were prepared using electrochemical codeposition under cyclic voltamm etric conditions. The composition of the PtRu alloy was altered by varying the concentration of Pt4+ and Ru3+ ions in the deposition solution. STM res ults demonstrated that the nm-PtRu film was composed of crystallites appear ing in a layered hexagonal form. The nm-PtRu/GC exhibited a high catalytic activity for CO oxidation, consisting mainly in a negative shift of potenti al for COad oxidation. In situ FTIR spectroscopic studies revealed that the nm-PtRu/GC alloy electrodes of different surface composition exhibit abnor mal infrared effects (AIREs) as observed on electrodes of nanometer scale t hin films of transition metals. The AIREs observed on nm-PtRu/GC electrodes consist in the inversion of COad bands, the significant enhancement of IR absorption and an increase in the FWHM. Following the increase in Ru compon ent in the nm-PtRu thin film the FWHM was increased progressively from 20 c m(-1) on a nm-Pt/GC to 55 cm(-1) on a nm-Ru/GC electrode, and the enhanceme nt factor of IR absorption by COL was between 10.5 to 13.1. The present stu dy has provided new understanding of the structure and properties of nanome ter scale thin film PtRu alloy material, and highlights its potential for f uel cell applications.