The Zinc Oxide-Copper Catalyst for Carbon Monoxide-Shift Conversion. II. The Catalytic Activity and the Catalyst Structures

Abstract

Abstract Structures of the zinc oxide-copper catalysts, whose catalytic activity in carbon monoxideshift conversion had been determined, were investigated by X-ray diffraction technique, mercury and helium-volume measurement, and electron microscopy. The electron microscopic observations were conducted in two ways; one on a catalyst sample after the activity test and the other on a raw sample while undergoing specified treatments in a reaction chamber attached to the electron microscope. On the basis of models of particle geometry obtained from the electron microscopic images, the results on pore volume, average diameters of pores and particles, all dependent on the method of preparation and the chemical composition, are explained. The models and the observed dependency of the specific activity of copper surface on the copper content indicate that the finer copper particles, whether patch-like or massive, show the higher specific activity. The fine copper particle is apt to be oxidized more readily than the well-grown particle.