Interaction of CO with CaO surfaces: A TPD and FTIR study

By using temperature-programmed desorption (TPD) gas analysis, thermal desorptions of C16O and C18O were observed at peak temperatures of 460 and 430 K, respectively, after C18O exposure at room temperature on CaO powders. By using FTIR measurements, C16O adsorption produced main IR bands at 1606 and 1316 cm−1 (assigned to carbonate-type species), which disappeared after heating up to 500 K under condition of high vacuum. Oxygen exchange between C18O and Ca16O may occur through a CO3-type intermediate on the surfaces, involving a lattice oxygen to produce the C16O TD peak.