ON THE ROLE OF ADSORBED ATOMIC OXYGEN AND CO2 IN COPPER-BASED METHANOL SYNTHESIS CATALYSTS

The role of adsorbed atomic oxygen in methanol synthesis is investigat ed by a series of transient experiments of the interaction of CO and C O2 with a ternary Cu/ZnO/Al2O3 catalyst under methanol synthesis condi tions. In particular, the response of adding CO and CO2 as pulses and as steps to the reaction gas mixture is studied. Hereby it is possible to study both the formation Of CO2 from the reaction of adsorbed atom ic oxygen (O-) with CO, and the dissociation of CO2 in situ, i.e., wh ile the catalyst is producing methanol. The experiments show no eviden ce of a significant coverage of O- under methanol synthesis condition s. In addition, it is shown that CO2 is the main carbon source in meth anol synthesis under the given conditions.