For example, when TiO2/GO tested under irradiation of UV light produces methanol, but when it is experimented under irradiation of visible light produces methane.
It seems active sites under UV and visible light are different which lead to different photocatalytic mechanism and eventually different products. Under UV domains of TiO2 might be more active leading to formation of methanol and activity of GO domain might be more dominant leading to methane formation.