Heterogeneous (2D) photocatalysis, surface only, works by photoreduction of the adsorbed substances in a liquid medium. The question then arises as to which substances that are not in contact with the surface of the catalytic material will not simply be neither adsorbed nor transformed?
I think it depends on the substance (pollutant) in the aqueous medium. Two types of reactions are taking place, ie photolysis and photocatalysis, we have seen that without photocatalysts the pollutant decolorize or degrade, this means that photolysis is the governing phenomenon, but in the presence of photocatalyst the reaction is fast and takes lesser time to degrade.
So, if the substance is not adsorbed on the surface, chances are there that it shall degrade, even the ROS produced by water splitting shall degrade these substances.
We have seen the effect of light in our recent publication (attached).
Article Photocatalytic Decolorization and Biocidal Applications of N...