Mesoporous titanium dioxide films have attracted attention in recent years due to their potential application in electrochromic devices, sensors, photocatalysis and solar cells. Such material possesses large effective surface area and pore volumes which facilitate educt/product transportation into/out of the structure. This, in turn, leads to enhanced reactivity. On the other hand, the porous nature of the material constitutes an unexpected high resistance for electron transport across the semiconductor network and impedes the electron collection efficiency of the films. In this work, mesoporous titanium dioxide films were synthesized via a sol-gel method. The surface area and porosity of the films were adjusted by varying the humidity during dip-coating process. The photoelectrocatalytic activity of the films towards water and organic contaminants were quantitatively evaluated in a photoelectrochemical cell. The photoelectrocatalysis reactions resistance was measured and used to express the electron transport characteristics of the films.