An STM, TPD and XPS investigation of formic acid adsorption on the oxygen-precovered c(6x2) surface of Cu(110)

X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption ( TPD) and scanning tunnelling microscopy (STM) have been employed to investi gate the adsorption of formic acid on O-c(6 x 2)/Cu(110) at 300 K. Formic a cid adsorption results in the production of adsorbed formate. TPD profiles indicate that the formate decomposes predominantly via dehydrogenation, wit h two peak maxima being observed at 415 and 460 K. Following complete decom position of the formate, approximately one-third of the oxygen in the origi nal O-c(6 x 2) overlayer remained adsorbed in the (2 x 1) and c(6 x 2) stru ctures. A number of adsorbate-related structures were observed with STM upo n formic acid adsorption and subsequent annealing. These included (3 x 1) a nd a structure containing bands of similar to 15 Angstrom width aligned in the [001] direction. After saturation exposures of formic acid the overlaye r arrangement is complex, probably containing a formate bilayer with format e adsorbed on top of formate bound directly to the Cu(110) substrate and ad sorbed formate on other areas of reconstructed O-c(6 x 2). (C) 1998 Elsevie r Science B.V. All rights reserved.