Preparation Of Novel Photocatalytic Thin Film Materials And Their Photocatalytic Properties

In recent years,much attention has been paid to the energy and environment problems,which are the most urgent questions facing mankind today.In order to solve them,many people are focusing on the technology of photocatalytic,because it can be used to fully decompose water to get hydrogen and purify environmental pollutants in some ways.Especially,photocatalytic hydrogen production is one of the important modern technology,due to its low-cost,high capability of energy storage and light conversion.Therefore,the technology of photocatalytic has the great significance on environmental protection and management.So far,the main problems and possible solutions about the research of photocatalytic materials are as follows:?1?much of the research works are mainly concentrated in the making of powder catalyst,thus leading to the difficulties of separating;but to some extent,using the thin photocatalytic material may solve these problems;?2?because the photoresponse of the photocatalytic material can affect the utilization of sunlight,broadening its light absorption range is the most likely to bear fruit;?3?the combination of photogenerated electrons and holes is one of the main factors affecting the performance of photocatalyst.How to design effective structures and promote the separation of photogenerated electrons and holes are very useful to scale out applications of photocatalytic technology.In this paper,many kinds of photocatalytic materials are made and studied in three major areas:?1?Preparation of mesoporous single-crystal titanium dioxide films by sol-gel method: the mesoporous single-crystal materials have a large specific surface area,which is beneficial to the transportation of electron,thus these maaterials may significantly improve the photocatalytic performance.In this section,the morphology and crystal phase of the films were controlled by adjusting the ratio of Ti to F and calcination temperature.The crystallinity,morphology and crystal phase of the films were characted by XRD,SEM,TEM,XPS and so on.The photocatalytic activity of mesoporous single crystal TiO₂ was studied by photocatalytic hydrogen production through using ethylene glycol as the sacrificial agent,and sodium sulfate as the electrolyte.?2?Preparation of Au/TiO₂ nanoparticles by sol-gel method: Au nanoparticles have strong plasma resonance,which can effect on the visible light?400-800 nm?.The interface hot electrons are generated on the surface of Au nanoparticles,then the hot electrons can be transfered from them and arrive at the conduction band of TiO₂.The Schottky barrier can not only contribute to the aggregation of hot electrons on the conduction band of TiO₂,but also effectively prevent them returned to the Au surface.Therefore the photocatalytic electrons and holes were easily separated.It is greatly to improve the photocatalytic performance of the sample under visible light.?3?Piezo-driven separation of photo-generated charges has recently been one of the most powerful strategy to improve photocatalytic efficiency.In this section,it is found that the effect of fluid eddy induced piezotronic can enhance the photocatalysis of ZnO,where the nanorods arrays of which vertically grow on a 3D nickel foam substrate.Though controlling the stirring rate of the magnetic stirrer,eddy current in the Ni foam skeleton is formed.Especially,deformation of nanorods caused by the flow of the solution can lead photo-generated charges separation easily,which is called as piezoelectric field.Therefore,the higher stirring speed,the higher photocatalytic oxidation of organic pollutants activity could be gotten.Such work provides a new way to design and fabricate novel piezo-photocatalytic materials for the real world application.