Electrochemical promotion of Pd for the hydrogenation of C2H2

Abstract

The effect of Non-Faradaic Electrochemical Modification of Catalytic Activity, orin-situ controlled promotion, was investigated during Acetylene selective hydrogenation on Pd films deposited on β″ - Al2O3, a Na+ conductor, at temperatures from 60 to 100 °C and GHSVs from 103 to 104 h-−1, i.e., under conditions similar to those used in industrial processes. It was found that both acetylene conversion and hydrogenation selectivity can be affected by means of externally applied potentials, i.e., by supplying or removing sodium ions to or from the catalyst surface. Electrochemical sodium supply to the Pd catalyst surfaċe was found to supress both the rate of acetylene hydrogenation and, to a larger extent the rate of ethylene hydrogenation to ethane. Consequently electrochemical sodium supply was found to enhance the selectivity to ethylene. Thus, β″ - Al2O3 can act as an active catalyst support causing enhanced performance of the Pd catalyst. Acetylene conversion and hydrogenation selectivity values up to 90 % and 95 %, respectively, were obtained.