Particle size effect of Ag-nanocatalysts deposited on carbon as prepared by gamma-radiation induced synthesis

摘要

The effect of silver particle sizes on the catalytic performance of Ag/C electrodes for oxygen reduction reaction (ORR) was studied. The Ag particles were precipitated from AgNO3 solutions on Vulcan XC-72 carbon as support by gamma-radiation induced synthesis method. The structural and morphological characterizations of the electrode materials were done by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that particles with smaller diameters, 11 +/- 6 nm, possess higher catalytic activity for ORR (50 mA/cm(2) at 0.3 V) as compared to those with larger diameters, 41 +/- 5 nm, ORR activity is 25 mA/cm(2) at 0.3 V. The observed effect may be explained by an increased amount of low coordinated atoms in smaller particles as compared to the larger ones.