The Formation of Methoxy from Methanol on an Oxygen Covered Cu(100) Surface at Temperatures of 90−200 K

The reaction of methanol with a preoxidized Cu(100) surface in the temperature range of 90−200 K has been studied with reflection−absorption infrared spectroscopy (RAIRS). Methanol is found to form methoxy (CH 3 O) at or below 90 K. The OH stretch vibration at 3550 cm -1 of a surface hydroxyl group (OH(ad)) appears as a small feature superimposed on the broad and much more intense OH stretch of adsorbed methanol at 3300 cm -1 . The assignment of the peak at 3550 cm -1 to OH(ad) is supported by its shift to 3540 cm -1 when preadsorbed 18 O is used in place of 16 O. The peak due to OH(ad) disappears upon annealing to 150 K, presumably due to further reaction with methanol to produce additional methoxy.