Electrochemical oxidation of propene using a membrane reactor with solid electrolyte

Abstract

A fuel cell type reactor with an oxide ionic conductor, for example, yttria-stabilized zirconia (YSZ), for the selective oxidation of hydrocarbons can serve as an “oxygen pump,” by which the oxygen flux transferred across the YSZ can be controlled by the electric potential externally applied between the anode and cathode. The application of electrochemical cell, using the YSZ for the oxidation of ethene, ethylebenzene, and methane over metal or metal oxide catalysts, as the anode, has been studied. Furthermore, it had been demonstrated that a ceria-based solid electrolyte (CeO 2 )0.8(LnO 1.5 ) 0.2 — where Ln = Sm, Gd, Y—is an attractive candidates for use in an electrochemical reactor for the selective oxidation of propene at relatively low temperatures. This is because of the high oxide ionic conductivity at the low temperature of 350°C compared with that of YSZ. This chapter discusses the investigation of a ceria-based solid electrolyte coated with YSZ to inhibit the complete oxidation of propene at the surface of CeO 2 as well as the selectivity to partial oxidation to acrylaldehyde. An electrochemical cell system with ceria-based solid electrolyte coated with YSZ prepared by the spin coating method showed higher selectivity to acrylaldehyde than that with ceria-based solid electrolyte alone. This may be because of the fact that a film of YSZ on the ceria-based solid electrolyte to suppress the complete oxidation of propene. When the YSZ|SDC disk was used as an electrolyte membrane, selectivity of the oxidation products did not depend on the thickness of YSZ.