Preparation And Photocatalytic Properties Of Au Decorated TiO₂ Ordered Composite Films

Recently,the problem of energy shortage and environment pollution has become more and more serious.Development of new energy resources and degradation of pollutants using heterogeneous photocatalysis technique have induced extensive attention.TiO₂ has been considered the ideal photocatalytic materials and obtained deeply studies due to its outstanding physical and chemical properties.However,the practical application of TiO₂ has been greatly restricted by its recombination of photogenerated charges and lower reaction efficiency.To enhangce the photocatalytic efficiencies,Au decorated TiO₂ ordered composite thin films have been designed and fabricated using two mainly methods,which including noble metal deposition and ordered porous microstructures.The main works are as following:1.The effects of proportion of monomer/dispersion medium and alcohol water ratio and monomer feeding rate on diameter of PS microspheres and its size distribution were studied,respectively.In addition,highly ordered and colloidal crystals were assembled by centrifugal sedimentation method using the PS microspheres synthesized above.2.PS colloidal crystals were filled with TiO₂ sol using sol-gel dip-coating method,then ordered porous TiO₂ films could be prepared by high temperature calcining.The influence of precursor concentration and calcination temperature on microstructure of the ordered porous TiO₂ was also discussed.To obtain highly ordered porous TiO₂ films,the optimum precursor concentration and calcination temperature are 0.4⁰.6mol/L and of 400⁴50?,respectively.3.Au decorated TiO₂ ordered composite thin films with different pore size from 0.9 to 4.2?m were fabricated using colloidal gold deposition method.The internal connection on microstructure and catalytic performance were also discussed.The Results show that microstructure has a significant influence on the photocatalytic activity of the Au decorated TiO₂ ordered composite thin films.With the increase of the pore size,the photocatalytic performance increases rapidly then decreases gradually,and reaches highest when the pore size is 2.2?m.With the change of the microstructure,effective active area and channel transmission efficiency of the composite thin films also varies.And ultimately,the highest catalytic performance could obtain when the competition between of the effective active area and the channel transmission efficiency achieve to a delicate balance at a particular size.