Photochemistry of iron pentacarbonyl adsorbed on titanium dioxide

The photolysis of iron carbonyl (Fe(CO) 5 ) adsorbed on titanium dioxide (TiO 2 , anatase) was studied by FT‐IR spectroscopy. When adsorbed Fe(CO) 5 is illuminated by visible and near‐UV light, the IR spectrum of its photolysis products is hardly observed, indicating that most of the Fe(CO) 5 is photodecomposed to iron(0) or iron oxides on TiO 2 . The carbon monoxide (CO) evolution rate upon illumination depends on the wavelength of light; 433 nm light is more effective for CO evolution than 366 nm light. This result implies that the band‐gap excitation of TiO 2 has little effect on the photolysis of adsorbed Fe(CO) 5 , since the absorption edge of TiO 2 (anatase) lies at around 400 nm. The effects of substrates on the photolysis of adsorbed Fe(CO) 5 are discussed with reference to previous results obtained for aluminium oxide (Al 2 O 3 ) and silicon dioxide (SiO 2 ), on which the photolysis leads to the formation of Fe 2 (CO) 9 or Fe 3 (CO) 12 .