Bridging the Gaps Between Experimental and Mechanistic Catalysis Research: A Case Study with CO Oxidation Over a Pd/Al2O3 Catalyst

Abstract

AbstractTemperature (T), concentrations of the reactants (C), and the corresponding reaction rate (r) are three important quantities for catalyst evaluation especially for mechanistic studies, however, even today experiments have not strictly met the needs. In this work, CO oxidation reactions are conducted over a Pd/Al2O3 catalyst. It is found that steady‐state tests together with the use of catalyst front temperature are necessary to reveal the average intrinsic catalytic performance. More importantly, for the first time, analytical solutions are obtained for T, C, and r within the catalyst bed from solving the differential equation governing general energy balance in the reaction system. Subsequently, it is found that the conventional differential reactor conditions do not result in accurate measurement of true reaction rate as generally believed. The reaction appears to follow a reaction mechanism below 50 % CO conversion probably involving chemical bond cleavage with an apparent activation energy of 194 kJ/mol while above 79 % conversion a 15 kJ/mol activation energy is observed suggestive of diffusion being the rate determining step.