Fractal dynamics of Heterogeneous Photochemistry on CH3OH/TiO2(110) Surface

We report direct evidence of methanol photodissociation on stoichiometric TiO2(110) detected by time-resolved two-photon photoemission (2PP) spectroscopy. The rise of an excite resonance in the 2PP spectra on the CD3OD/TiO2(110) surface as a function of laser illumination time strongly suggests that the observed excited resonance is photoinduced by the 400 nm laser. The appearance rate of the excited resonance is strongly dependent on the laser power. A large isotope effect on the appearance rate of the excited resonance has also been observed. Based on these experimental results along with results of previous experimental and theoretical studies, we believe that the excited resonance observed in the 2PP spectra is possibly due to methanol photodissociation on the TiO2(110) surface in which the hydroxyl hydrogen on methanol is transferred from the methanol oxygen atom, which is bonded to the Ti4+ sites, to the nearby bridge bonded oxygen (BBO) site. The dynamics of the photoinduced chemistry of methanol on TiO2(110) appears to fractal, this gives a clear insight into the nature of photochemistry of TiO2