Cu/ZnO-based water-gas shift catalysts in shut-down/start-up operation

摘要

The water-gas shift performances of Cu/ZnO and Cu/ZnO/Al2O3 catalysts in the challenging shut-down/ start-up operation were investigated. The Cu/ZnO catalyst showed comparable activity to the Cu/ZnO/ Al2O3 catalyst but better stability in shut-down/start-up cycles, although the latter had much higher Cu surface area and smaller Cu crystallite size. The Cu-ZnO interface sites were thus suggested to participate directly in the reaction. Based on the characterizations, the deactivation of the Cu/ZnO/Al2O3 catalyst was mainly attributed to the loss of active sites due to the formation of carbonate species rather than the sintering of Cu crystallites.