Au反点阵列孔径对Au/TiO_2复合薄膜光催化性能的影响

EFFECT OF PORE SIZES OF Au ANTIDOT ARRAYS ON PHOTOCATALYSIS PERFORMANCE OF Au/TiO_2 COMPOSITE FILMS

通过对胶体晶体模板的反向复制,制备了反点阵列孔径各异的Au/TiO2复合薄膜.采用SEM,AFM,XRD,UV-Vis和四探针测试仪等手段对复合薄膜的结构和光催化性能进行了表征.通过对胶体晶体模板和反点阵列几何模型的计算,讨论了Au反点阵列在TiO2薄膜表面的覆盖面积与模板中微球粒径的关系.结果表明:反点阵列孔径对复合薄膜的光催化性能有显著影响.孔径增大,使反点阵列的导电性能提高,载流子的输运效率增强,促使光催化性能的提高;同时,孔径增大又造成光生电子向反点阵列迁徙过程中的复合几率加大,反而使光催化性能降低.2种作用共同导致了Au/TiO2复合薄膜的光催化性能随Au反点阵列孔径的增大出现先提高后降低的变化规律,并在孔径为3.3μm时达到最高.

Au/TiO2 composite films with different pore sizes of antidot arrays are prepared by inversion replication of colloidal crystal templates.The microstructure and the photocatalysis performance of all samples are characterized by using SEM,AFM,XRD,UV-Vis and four-point probe.Relations between the coverage of antidot arrays on the surface of TiO2 films and the diameters of template microspheres are discussed through calculation on geometric model of colloidal crystal templates and antidot arrays.The results show that the pore size of Au antidot arrays significantly influences the photocatalysis performance of the composite films.With the pore size increasing,the conducting ability and the charge carriers transport efficiency enhances.This is responsible for the improvement of photocatalysis performance.At the same time,the recombination probability of photoinduced electrons and holes increases during the charge carrier migration with the pore size decreasing,which result in the decrease of the photocatalysis performance.The photocatalysis performance increases rapidly and then decreases gradually with the pore size increasing,which is the result of the aforementioned two aspects of factors.The photocatalysis performance of the composite films reaches the maximum value when the pore size of Au antidot arrays is 3.3 μm.