This book deals with the roles of photocatalytic reactions of platinized TiO2 nanoparticles, and study the parameters that effective on photo oxidation and photodehydrogenation from aqueous solution of methanol with bare and platinized TiO2 such as, dose of catalyst, concentration of methanol, initial of pH, temperature and effect of dose, pH, temperature on quantum yield of photo-reaction. Then, measured the Physical Characterizations of Catalysts, such as Atomic Absorption Spectrophotometry(A.A), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction Spectroscopy (XRD), Atomic Force Microscopy (AFM) and Band Gap Energy(Bg). moreover, suggested a suitable mechanisms for photo oxidation and photodehydrogenation from aqueous solution of methanol with bare and platinized TiO2.