METHANOL SYNTHESIS OVER CATALYSTS DERIVED FROM CECU2 - TRANSIENT STUDIES WITH ISOTOPICALLY LABELED REACTANTS

The transient response of activated CeCu2-derived methanol synthesis catalysts to pulses of isotopically labelled CO, C02, and 02 has been determined under a variety of conditions. These data are supplemented by appropriate H/D exchange and TPD measurements. The results confirm previous studies on related catalysts showing that methanol is synthesized by hydrogenation of CO and not C02. They also show that the active catalyst surface is extensively covered with a hydrogen-deficient methanol precursor under steady-state conditions and that the cerium oxide surface or its interface with the copper crystallites is intimately involved in the synthesis process. Transient exposure to oxidizing gases (e.g., C02 and 02) causes displacement of the precursor, giving an increased yield of methanol. Higher levels of exposure lead to the formation of strongly bound C02-derived complexes on the oxide surface: these quench the high synthesis activity. © 1992.