Solar Photocatalytic production of hydrogen from aqueous polystyrene-Pt/TiO2 Suspension

Abstract

       In the present work, the Photocatalytic production of hydrogen from aqueous suspension of polystyrene is studied using titanium dioxide doped with platinum as photocatalyst. The parameters affecting the efficiency of Photocatalytic hydrogen production are Pt-loading (%), solution pH and the Pt/TiO₂ loading and particle size.  Under optimum conditions, 78 micro moles of hydrogen gas is generated after about 25 hr, irradiation in deacrated solution  ( pH=13, Pt weight % load is 6% and Pt/TiO₂ load and particle size are 4 gm/l and 400 mesh size respectively). Negligible amounts of hydrogen gas were noticed in the presence of unplatinized TiO₂ at pH lower than 4. The apparent quantum yield of the Photocatalytic production of hydrogen was also determined and is affected by the % load of Pt on TiO_2. The number average molecular weight of polystyrene decreases with irradiation time which indicates the photo degradation process under the condition employed. Carbon dioxide is also evolved at the later stage of photolysis process which suggests the partial mineralization of the polymer during the photolysis process. According to the experimental results a mechanism of hydrogen generation and polymer degradation is suggested.