Study On The Characteristics And Preparation Of Vertically Oriented Mesoporous Film By Electrodeposition

Mesoporous silica materials with larger specific surface areas, large pore volume, and fine-tuning of the pore structure hold broad application prospects in the field of catalysis, adsorption, separation, optoelectronics, et al, which has been received deep exploration. Mesoporous silica films with ordered arrangement of mesochannels make it possible in the application of devices.Particularly, the application research on highly ordered and vertically oriented mesoporous silica films has attracted attention of scientists from all areas in recent years. At present, the development of application of the film is that its vertical tunnel can be used as template to grow metal nanowire arrays and some optically active molecules, on the other hand, it also can be used as electrochemical sensor and optical devices.Mesoporous silica films with highly ordered and vertically oriented channels can be successfully generated by electrodeposition. This method involves the electrogeneration of hydroxide ions at an working electrode surface immersed in an hydrolyzed sol solution (containing typically TEOS and CTAB) in order to catalyze polycondensation of the precursors and self-assembly of hexagonally packed one-dimensional channels that grow perpendicularly to the ITO glass surface. Here we study the affection of the supporting electrolyte to the hydrolysis of TEOS and to the process of the electrodeposition, which indicates that Neutral nitrate is the best supporting electrolyte.Here we use small angle XRD, SEM and TEM to observe the arrangement of the channel, surface morphology and mesochannel’s structures, showing orderly arrangement of the mesostructure. Voltammetric experiments carried out on these mesoporous films deposited onto planar indium-tin-oxide electrodes, after template extraction, have revealed very sensitive responses to solution-phase redox probes as a result of fast mass transport from the external solution through the film to the electrode surface, this result enabling characterization of thin films directly on their underlying ITO glass surface.TEM image shows that the microstructure of oriented mesostructured film is quite similar to that of metal and semiconductor polycrystalline films which grow in a specific crystallographic direction. Ellipsometry is used to analysis the thickness of thin films changing over deposit time under different sedimentation potential. The transparence curves of the films is measured by UV—visible recording spectrophotometer, which revealing that the mesoporous film is a reflectance-decreasing film. The result also shows the as-deposited films are amorphous and with great porosity.