The Synthesis Of Near-infrared Surface Plasmon Resonance Cu₂S Quantum Dots And The Photocatalytic Activity Of Their Composite Semiconductor

Environmental pollution and energy crisis are two big worldwide problems in mankind today.Photocatalysis is expected to become one of the most effective ways to solve these problems.Nowadays,most semiconductors such as TiO2 or ZnO has poor light response ability with low quantum efficiency,which makes it difficult to obtain large-scale practical application.Thus,Broadening light absorption ability of photocatalyst and improving the efficiency of photocatalysis are two main goals of the photocatalytic technology research.Ion doping,dye sensitizing,quantum dots sensitized,precious metals loading and semiconductors composite have proven to be the important means for the preparation of efficient photocatalysts.However,nowadays broadening range is mainly concentrated in the visible light absorption area,and most light distribution in the near infrared region is not fully utilized.Therefore,to explore the photocatalytic materials with near infrared absorption of light and the mechanism of photocatalytic processes of these photocatalyst is undoubtedly great significance in developing highly efficient photocatalysts and the science in the field of photocatalysis.The thesis explore that the synthesis of Copper(I)sulfide(Cu2S)which owns Near-Infrared Localized Surface Plasmon Resonance(NIR-LSPR),the NIR-LSPR can tune by the ratio of oleylamine and oleic acid in the process of synthesis.At the same time,we characterized in detail their chemical components,structures,morphologies,the reduction of carbon dioxide photocatalytic activity and so on.The composite material was constructed by mix different ratio of Cu2S quantum dots with TiO2,and the nature of the enhancement of photocatalytic reduction of carbon dioxide activity for Cu2S-TiO2 was systematically studied based on the results of various physical and chemical characterizations.The Cu2S sensitized ZnO nanorod array was constructed via the electrostatic self-assembly,and the mechanism and the activity of phtocatalytic reduction of carbon dioxide was studied in detailed,at the same time,the application of Cu2S quantum dot was broadened to the device.The main results and conclusions obtained in this work are presented as follows.(1)Cu2S quantum dots has the strongest Surface Plasmon Resonance absorbtion in the Near-infrared,when the ratio of oleylamine and oleic acid was one at the situation of inert gas during the synthesis.(2)The Cu2S-TiO2001 was constructed via ultrasound and stirring Cu2S quantum dots with TiO2 001 in the alcohol solvent.It was confirmed that the enhancement of photocatalytic activity was resulted from the NIR-SPR of Cu2S quantum dots by various wavelength of light;Under the solar spectrum,when the weight of Cu2S quantum dots was 3%,the composite material owned the best activity,methane production was nearly three times of pure TiO2001,(3)The water soluble Cu2S quantum dots was got by ligand exchange with mercaptoacetic acid;the Cu2S sensitized ZnO nanorod array was constructed by electrostatic self-assembly,the sensitized photocatalyst owned nearly 9.6 times photocatalytic reduction of CO2 activity than pure ZnO nanorod array;Compared to simple mixed samples,the sensitized material improve more activity,so the hot electron produced by sensitized material moves fast.These results demonstrated the influence factor of the Near-Infrared Surface Plasmon Resonance(NIR-SPR)of Cu2S,and certified that the NIR-SPR of Cu2S is the main reason of the enhancement of photocatalytic activity in the composite photocatalyst.The application of Cu2S was enrich,and impulse the research of Near-infrared absorbtion photcatalsis.