Catalyst particles with nonuniform activity distribution may exhibit higher activity

selectivity and improved poison and deactivation stability as com-pared with those which uniform distribution. Theoretical and experimental work in this area prior to 1986 has been reviewed by Dougherty and Verykios

but expect Juang and Weng

the papers of Chinese scientists have not been included. In this paper

the literatures on the intra-particle behavior of nonuni-formly distributed catalysts are reviewed

covering the theoretical models of single and complex reaction networks under isothermal and nonisothermal conditions

experimental studies and analytical approach of activity profile optimization. Papers of Chinese authors and more recent achievements up to 1989 are also reviewed. The review tries to systematize the expressions of local rate constant and activity distribution used in the literature

and give a general theoretical model which can be applied to any single or complex reaction network the Thiele modulus is also expressed in a generalized form.