Design And Synthesis Of High Efficiency Nano - Photocatalytic Composites

In recent years, application of semiconductor photocatalyst in energydevelopment and environmental has attracted extensive attention of governments andscientists around the world. Research and development on high efficient catalyst is themost important task for the study of photocatalytic. TiO2and WO3is becoming theideal photocatalytic materials for their unique performance. However, Individualsemiconductor photocatalyst has low quantum efficiency and low solar energyutilization problems, which restrict its application in industry. The nanocomposite canincrease the material surface area, the active sites and dynamic conditions to improvethe photocatalytic activity by simple combine two material together. Thenanocomposite can also increasing the quantum efficiency of single semiconductor,extending the light-response range, improving the light stability and thermal stability.So it has become the focus of semiconductor composites research. Therefore, ourresearch work is mainly based on the following points: First, how to designappropriate combination of methods to increase the contact surface or to enhance theinteraction between the components. Second, how to design the active center of acatalyst in order to achieve rapid transfer or separation of photo-generated electronsand holes, thereby to explore the high catalytic activity of catalyst. Third, how todesign and build a multi-level structure photocatalyst to improve the light useefficiency and fully play the role of catalyst components, thus, to design low cost butefficient photocatalyst. The specific work consists of three parts:1. The research on adsorption-photocatalytic performance of single-crystal WO3with surface wrapped by grapheneSynthesize WO3nanorods in the clean water medium conditions introduced withwrapped by graphene by a simple method. Due to chemical and electrostaticinteractions, graphene tightly wrapped on the surface of the WO3nanorods. UsingRhB dye as the probereaction, we test the adsorption and photocatalytic properties ofthe composite materials. The results show excellent performance, which can be ascribed to: First, the composite materials retained the adsorption properties to someextent of WO3nanorods; Second, photogenerated electrons transfer to graphene andextending the seperation time of electron-hole pair, which make the catalyst showgood visiblelight catalytic properties.2. The research on photocatalytic performance of nanocrystaline TiO2loaded ongrapheneBy the method of in situ high-temperature solventthermal method, we preparevisible light catalyst of nanocrystaline TiO2loaded on graphene. We test the ability ofhandling dyes in the water and photocatalytic decomposition of water into hydrogen.We hace studied the loading mount of TiO2and active sites of the catalytic. Thestudies show that TiO2dispersed well on graphene, which facilitates the absorbance oflight. Morever, it is better that Pt dispersed on TiO2than on graphene for hydrogengeneration. Experimental results show that the interaction between the active sites andthe distribution between the catalyst component of catalyst are significant factors tobe considered when design catalytic.3. The research on photocatalytic performance of nanocrystaline TiO2modifiedflower-like structure MoS2First, we synthesized flower-like shaped MoS2as supporter and modified bynanocrystaline TiO2under high-temperature solvethermal condition. The catalystsshow excellent photocatalytic decomposition of water without Pt, which can beascribed to three points below: First, nanocrystaline TiO2dispersed well on MoS2;Second, the open structure of MoS2is in favor of light absorbance; Third, the specificstructure of MoS2can expose more acitve sites, which can replace noble metal Pt. Theresults also show that the composites has longer catalytic life and can be reused sixmore times.