Adsorption and photolysis of trimethyl acetate on TiO2(B)(001) studied with synchrotron radiation core level photoelectron spectroscopy

• We present a synchrotron radiation photoelectron spectroscopy study of the adsorption and photooxidation of trimethyl acetate (TMA) on TiO2(B)(001). The TiO2(B)(001) substrate was realized in the form of 2nm thick film on Au(111). The TMA species adopt the bidentate bonding configuration, as expected for carboxylic acids on TiO2, but cannot coordinate to all surface Ti ions due to steric hindrance. The proposed arrangement of the TMA species thus allows for the formation of an overlayer with a (2 x 1) periodicity. The thermal stability is found to be comparable to that on rutile (110) although the results indicate differences in the threshold for the TMA+H -> TMAA reaction. Photolysis using both ultraviolet (UV) light and soft x-ray synchrotron radiation (SR) was studied and compared to the reaction on the reduced ruffle (110) surface. A kinetic analysis suggests that the photoreaction rate for TMA on the TiO2(B) thin film is initially two times faster than that on the reduced rutile TiO2(110) surface. The higher activity of the TiO2(B) film is assigned to a reduced influence from surplus electrons associated with reduced Ti species, thereby decreasing the probability for hole-annihilation at high TMA coverage.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

Nyckelord

Titanium dioxide

Photocatalysis

Photoelectron spectroscopy

TiO2(B)

Adsorption

Carboxylic acids

Adsorption

Carboxylic acids

Photocatalysis

Photoelectron spectroscopy

TiO(B)

Titanium dioxide

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