TiO sub(2)/WO sub(3)/Au nanoarchitectures' photocatalytic activity "from degradation intermediates to catalysts' structural peculiarities" Part II: Aerogel based composites - fine details by spectroscopic means

The "build-up" methodology of a composite photocatalyst is a critical issue regarding the showed photo-catalytic performance, including the formation of intermediates. To investigate this issue TiO sub(2)/WO sub(3)/Au aerogel composites were obtained by sol-gel method and subsequent photoreduction (Au) with UV or visible light. The obtained composites' photocatalytic activity and intermediate formation profiles were evaluated using phenol as a model pollutant. XPS/UPS, XAFS and DRS were used to uncover local coordination, surface chemistry (of the different types of atoms (Ti, W, O and Au) and the band-structure (band-gap, possible electron transitions) of the obtained nanomaterials. The intermediates' evolution profile and structural peculiarities were successfully correlated and it was shown that each minor structural (bulk or surface) change has a significant impact on the photocatalytic activity and intermediate formation dynamics.