Heterogeneous catalysis is a topic very studied in science. Its application in technologies of energy conversion, water purification, chemical synthesis, car catalytic converter and so on is studied. Recently, the TiO2 material in anatase and rutile phases has been used extensively in photocatalytic systems; its band-gap is localized in visible and ultra-violet spectra, proportioning a good material for generation of chemical radicals. Nowadays, the density functional theory (DFT) is shown as a great tool to simulate all types of materials and the possibilities to simulate bulk and surfaces of materials importance in last few decades. Recently, quantum periodic calculations based on DFT methods have been widely used to simulate materials and the main functionals applied are PBE, PBE0 and B3LYP; they are important for doping and adsorption theoretical investigations and are present in various simulation programs, such as, Crystal, Wien, Vasp and others. This methodology has investigate the influence of dangling bonds, cationic and anionic doping, charge transfer, surface energy and more quantum properties. Quantum chemistry tools, in particular, DFT methods, are key points to develop high quality research and technology once theoretical calculations are important to guide and understand the molecular design in photocatalysis
