Dissociation of formic acid on anatase TiO2(1 0 1) probed by vibrational spectroscopy

The interaction of formic acid with anatase TiO2 (1 0 1) has been monitored by infrared reflection absorption spectroscopy (IRRAS) using a novel ultrahigh vacuum (UHV) system. It was found that HCOOH molecules do not adsorb intact on TiO2 (1 0 1), as proposed previously, but dissociate yielding different formate species. The IR-bands observed in the IRRAS-data indicate the presence of a mono- and a bidentate species. It is proposed that the formation of the bidentate form requires the presence of oxygen vacancies.