UNIFORM COLLOIDS OF RUTHENIUM DIOXIDE HYDRATE EVOLVED BY THE SURFACE-CATALYZED REDUCTION OF RUTHENIUM TETROXIDE

Hydrosols of ruthenium dioxide hydrate comprising substantially monodi sperse, spherical, and pristine submicron particles have been synthesi zed by the reduction of aqueous ruthenium tetroxide. Subsequent to nuc leation, colloidal particles grow spontaneously by heterogeneously cat alyzing the reduction of ruthenium tetroxide by water. The kinetics of the growth process are described and a mechanism proposed whereby par ticles act as microelectrodes, coupling the anodic oxidation of water and the cathodic reduction of ruthenium tetroxide. Observed trends in particle size and size distribution are discussed in relation to the k inetic law of particle growth.