Ag-based electrocatalysts for ethylene epoxidation

Ethylene oxide (EO) is industrially produced by epoxidation of ethylene on Ag-based heterogeneous catalysts. Electrophilic oxygen species are assumed to be active key in the EO production. This study explores possibility electrochemically these a solid electrochemical cell. Two series Ag based cermet electrodes were prepared either with Yttria Stabilized Zirconia (YSZ), pure ionic conductor, or Gadolinia-Doped Ceria (GDC), mixed and electronic conductor. Ag/YSZ layers deposited planar tubular YSZ dense substrates using conventional chemical method while Ag/GDC cermets coated GDC pellets reactive magnetron sputtering. We evidenced self-redispersion ethylene/oxygen mixture leading formation small clusters close interaction which selective for epoxidation. However, sintering process too fast even at 260°C maintain selectivity. On other hand, selectivity towards conversion coatings found linearly increase applied current, demonstrating first time, direct electrooxidation into EO.