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 pH of solid oxide-aqueous slurries at very high solid to liquid ratios. A simple non-Nernstian model of the oxide charging along with the experimental results demonstrate a very strong buffering effect of common oxide surfaces at high oxide content. This provides a simple, accurate measurement of oxide PZC which compares favorably to other common methods for PZC determination. The ramifications of the buffering effect on catalyst preparation are discussed. (C) 1995 Academic Press, Inc.