3.2. Photoreduction of CO2
Blank tests, in the absence of TiO2 as well as in the
dark reaction, showed that there was no organic product
found for long periods of CO2 photoreduction. In all
cases, methanol was the main product. Ethanol, propanol,
acetone and other hydrocarbons might have been
generated, but in small quantities which is too low to
be detected. Photocatalytic activity is presented by a
product yield, e.g., lmol/(g catal.), and quantum efficiency
(UQ) that can be evaluated with Eq. (1) below
[1]. This calculation is based on methanol yield at 6 h
of the reaction.