We have studied nano-sized Au catalysts supported on Mg(OH)(2) and TiO2 usi
ng Au-197 Mossbauer spectroscopy. Au-197 Mossbauer spectra observed for Au/
Mg(OH)(2) catalysts can be decomposed into one singlet with zero isomer shi
ft and several doublets. One of the doublets shows an isomer shift that is
typical for Au-I, and other doublets are due to Au-III. The relative area o
f the Au-I component shows the maximum value for a specimen calcined at 523
K, which also shows the highest catalytic activity.