Surface self-cleaning efficiency depends on the rates of decontamination and contamination. It has been observed that the rate of decontamination increases when the surface is exposed to water, a process called as photoinduced superhydrophilicity. Understanding the reaction mechanism for photoinduced superhydrophilicity has been challenging over past decade. Several reaction mechanisms have been proposed but gaps in understanding these mechanisms elemental wise remain. Moreover, the reaction mechanisms proposed contradict the experiment results of the titanium dioxide interaction with water. Thus, it is essential to propose a reaction mechanism that is consistent with the experimental results. In the first part of the thesis, we fabricated titanium dioxide thin films by using the Atomic Layer deposition(ALD). Tetrakis-(dimethylamino) titanium (TDMAT) and ozone precursors are used to deposit photoactive titanium dioxide. Experiment results using these films are found to be promising. In the second part of the thesis, we proposed potential elementary reaction mechanisms in supporting experimental evidence at each step of the reaction.