Ethanol photocatalysis on rutile TiO₂(110): the role of defects and water

Abstract

In this work we present a stoichiometric reaction mechanism for the photocatalytic ethanol oxidation on TiO2(110).

Unravelling Site-Specific Photo-Reactions of Ethanol on Rutile TiO2(110)

“…In order to maintain the hole created by the addition of the OH Ti group, it is essential to use a stoichiometric rather than a reduced supercell 57 . In agreement with previous computational results 31 32 34 36 and TPD data 27 28 29 39 we found that the adsorption strength of molecularly (−0.79 eV) and dissociatively (−0.71 eV) adsorbed ethanol is strongest on-top on 5f-Ti sites and almost degenerated. Because the barrier for EtOH Ti dissociation via O–H bond scission is only ~0.28 eV 32 we consider the EtO Ti ethoxide ( Fig.…”

“…In surface science, where single crystalline surfaces can be studied at ultrahigh vacuum (UHV) conditions, particular focus has been on the interaction between EtOH and the rutile TiO 2 (110)–(1 × 1) surface 27 28 29 30 31 32 33 34 35 36 37 38 39 , because this surface is the most stable one of rutile and often serves as a model for transition metal surfaces 1 2 3 4 10 11 12 . The TiO 2 (110)–(1 × 1) surface consists of alternating rows of fivefold-coordinated titanium (5f-Ti) atoms (the Ti troughs) and protruding, twofold coordinated bridge-bonded oxygen (O br ) atoms.…”

“…The adsorption of EtOH and the thermally activated chemistry of EtOH on rutile TiO 2 (110)–(1 × 1) have been studied previously by means of photoelectron spectroscopy (PES) 28 30 44 , temperature-programmed desorption (TPD) 27 28 29 32 33 36 37 38 39 , femtosecond two-photon photoemission spectroscopy (2PPE) 36 , and scanning tunnelling microscopy (STM) 32 33 35 . In addition, the EtOH–TiO 2 (110) interaction has been studied using density functional theory (DFT) calculations 31 32 33 34 35 36 .…”

“…Some studies also addressed the photo-chemistry of EtOH on rutile TiO 2 (110) 30 31 36 37 38 39 . PES and TPD studies suggest that EtOH converts to acetaldehyde (CH 3 CHO) and, finally, acetate (CH 3 COO − ) under UV light illumination in an oxygen background 30 31 .…”

In Situ ATR-FTIR Investigation of the Effects of H2O and D2O Adsorption on the TiO2Surface

“…This result can tentatively be explained either by photoinduced charge transfer process or by the formation of water as an intermediate product. Lin et al proposed mechanism pathways of the formation of CH3COad, CO2, and H2O as photoproducts in the presence of O2 during the oxidation of ethanol [21,22]. Although, it is well known that the ethanol can be easily adsorbed onto TiO2 surfaces, however the adsorption mechanism of water and D2O on TiO2 surfaces are still unclear.…”