SIMPLE, ACCURATE DETERMINATION OF OXIDE PZC AND THE STRONG BUFFERING EFFECT OF OXIDE SURFACES AT INCIPIENT WETNESS

A special spear-tip semisolid electrode has been used to measure the p H of solid oxide-aqueous slurries at very high solid to liquid ratios. A simple non-Nernstian model of the oxide charging along with the exp erimental results demonstrate a very strong buffering effect of common oxide surfaces at high oxide content. This provides a simple, accurat e measurement of oxide PZC which compares favorably to other common me thods for PZC determination. The ramifications of the buffering effect on catalyst preparation are discussed. (C) 1995 Academic Press, Inc.