NONDISSOCIATIVE HIGH-TEMPERATURE INDUCED STATES OF CO FROM CO2 ADSORBED ON TUNGSTEN SURFACE NEAR ROOM-TEMPERATURE

Results regarding the thermal desorption of CO//2 adsorbed on tungsten near room temperature, studied by electron stimulated desorption (ESD), are presented. At temperatures lower than 600 K, the ESD CO** plus and O** plus ion currents behave similarly to ions coming from CO, namely the CO** plus and O** plus currents disappear at temperatures lower than 500 K. On the contrary, new states yielding CO** plus and O** plus are revealed at temperatures higher than 700 K; the former species can be identified as non-dissociative CO states and the latter one comes from both CO and O. A model reaction of the implied process at the different temperatures is also presented.