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

By using temperature-programmed desorption (TPD) gas analysis, thermal deso rptions of (CO)-O-16 and (CO)-O-18 were observed at peak temperatures of 46 0 and 430 K, respectively, after (CO)-O-18 exposure at room temperature on CaO powders. By using FTIR measurements, (CO)-O-16 adsorption produced main IR bands at 1606 and 1316 cm(-1) (assigned to carbonate-type species), whi ch disappeared after heating up to 500 K under condition of high vacuum. Ox ygen exchange between (CO)-O-18 and (CaO)-O-16 may occur through a CO3-type intermediate on the surfaces, involving a lattice oxygen to produce the (C O)-O-16 TD peak. (C) 2000 Elsevier Science B.V. All rights reserved.