Particular properties and structure of electrochemically prepared Pd film nano-materials

The Pd film nano-materials supported on glassy carbon (nm-Pd/GC) were prepared under conditions of electrochemical voltammetry, STM images illustrated that the Pd film consists of crystallites which are composed of nano-particles of Pd with average size at around 6nm, and are of layer shapes. CO adsorption on nm-Pd/GC electrodes manifested abnormal infrared effects (AIREs), i.e., the inversion of IR band direction and the enhancement of IR absorption, In comparison with CO adsorption on massive Pd electrode, an enhancement factor at 42.6 was measured on a nm-Pd/GC electrode of film thickness at 12.2nm, The nm-Pd/GC electrode possesses particular properties for hydrogen reaction, It was revealed that, in contrast to hydrogen absorption by massive Pd electrode, the surface processes of hydrogen adsorption-desorption become the dominant reaction on nm-Pd/GC electrodes, The results demonstrated also that both the AIREs for CO adsorption and the particular properties for hydrogen reaction depend strongly, on the thickness of Pd film, and can be consequently assigned to the nanometer size effect of Pd film materials. The present study has introduced important significance for further studies on surface electrochemistry and electrocatalysis.