本文關(guān)鍵詞： 光催化 異質(zhì)結(jié) 納米片 石墨相氮化碳 模特-肖特基效應(yīng)　出處：《湘潭大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著全球環(huán)境惡化日益嚴(yán)重,人們對環(huán)境污染問題逐漸重視,利用光催化劑將太陽能轉(zhuǎn)化為人類可以直接利用的能量,并用其解決地球資源的枯竭和生存環(huán)境的惡化是可再生清潔能源研究的一個重要方向。石墨相氮化碳(g-C3N4)作為一種新型的無污染環(huán)保型光電材料,有著廣闊的研究空間和應(yīng)用前景。本文以g-C3N4的納米復(fù)合材料為研究對象,分別通過聲化學(xué)方法和熱縮聚方法合成了三元復(fù)合納米材料g-C3N4/MoS2/GO和g-C3N4/MoS2/Ag。我們對合成的復(fù)合材料進行成分、結(jié)構(gòu)、形貌、光學(xué)特性等進行表征,通過對樣品的瞬態(tài)光電流響應(yīng)測試和交流阻抗測試表征其光電化學(xué)性能,通過光催化降解RhB溶液進行了光催化性能表征。而且,基于表征和測試結(jié)果對合成的三元復(fù)合材料進行了光生電子空穴轉(zhuǎn)移、分離和光催化機理分析。本文以g-C3N4納米復(fù)合材料的研究結(jié)果為界面的異質(zhì)結(jié)和原位耦合助催化劑的半導(dǎo)體催化材料設(shè)計和大規(guī)模生產(chǎn)提供了參考。主要結(jié)果如下:(1)通過簡易的聲化學(xué)方法制備了g-C3N4/MoS2/GO。制備的三元復(fù)合納米材料中超薄MoS2納米片和GO納米片大范圍地提高了可見光的吸收性能,進而促進三元復(fù)合納米材料產(chǎn)生更多的光生電子。MoS2納米片與GO納米片和石墨相氮化碳耦合,在g-C3N4/Mo S2和g-C3N4/GO界面形成兩類P-N異質(zhì)結(jié),這些異質(zhì)結(jié)產(chǎn)生的空間電荷層不僅有效地提高光生電子率,而且提高了電子空穴對的轉(zhuǎn)移、分離,有效地延長了光生電子空穴對的壽命。同時,超薄MoS2納米片和GO納米片是高遷移率的電子轉(zhuǎn)移媒介,進一步促進產(chǎn)生的光生電子空穴對在g-C3N4/Mo S2和g-C3N4/GO界面的轉(zhuǎn)移、分離。實驗表明合成的三元樣品g-C3N4/Mo S2/GO的瞬態(tài)光電流強度是純的g-C3N4樣品的1.8倍,其降解Rh B溶液的光催化效率是純的g-C3N4樣品的2.3倍,結(jié)果證明了制備的三元復(fù)合納米材料g-C3N4/MoS2/GO在可見光下較其它相關(guān)對比材料展現(xiàn)了更加優(yōu)越的光電化學(xué)性能和光催化性能。(2)利用AgNO3的多功能修飾性在三聚氰胺熱縮聚過程中復(fù)合MoS2納米片一步合成一種由g-C3N4、Ag和MoS2納米片組成的多孔三元復(fù)合納米材料g-C3N4/Mo S2/Ag。AgNO3熱解產(chǎn)生的氣泡作為一種額外的軟模板使三聚氰胺熱縮聚過程自組裝生成超薄g-C3N4納米片和多孔結(jié)構(gòu),提高了對光的吸收性能。金屬Ag和g-C3N4納米片之間自組裝耦合產(chǎn)生的納米級Mott-Schottky效應(yīng)不僅為電荷的轉(zhuǎn)移、分離提供了有效通道,而且調(diào)整了g-C3N4納米片的能帶。同時,g-C3N4納米片經(jīng)調(diào)整后的能帶結(jié)構(gòu)有協(xié)同作用,加快了光生電子空穴對在二維g-C3N4/Mo S2異質(zhì)結(jié)界面的轉(zhuǎn)移和分離。通過該方法合成的三元復(fù)合納米材料g-C3N4/Mo S2/Ag在可見光的照射下較其它相關(guān)對比材料,其瞬態(tài)光電流強度是純的g-C3N4樣品的大約3倍,其降解Rh B溶液的光催化效率是純的g-C3N4樣品的3.8倍,顯著提高了光電化學(xué)性能和光催化性能。
[Abstract]:With the worsening of the global environment, people pay more and more attention to the problem of environmental pollution, using photocatalyst to convert solar energy into energy that can be directly used by human beings. It is an important direction in the research of renewable clean energy to solve the depletion of the earth's resources and the deterioration of the living environment. Graphite phase carbon nitride (GN) g-C3N4) is used as a new type of pollution-free environment-friendly optoelectronic material. In this paper, the nanocomposites of g-C _ 3N _ 4 have been synthesized by means of sonochemical method and thermocondensation method, respectively, and g-C _ 3N _ 4 / MoS _ 2 / go and g-C _ 3N _ 4 / MoS _ 2 / Ag have been synthesized. The structure, morphology and optical properties of the samples were characterized. The photochemical properties of the samples were characterized by transient photocurrent response test and AC impedance test. The photocatalytic properties of the samples were characterized by photocatalytic degradation of RhB solution. Based on the characterization and measurement results, the photogenerated electron hole transfer of the synthesized ternary composites was carried out. Separation and photocatalytic mechanism analysis. The research results of g-C _ 3N _ 4 nanocomposites provide references for the design and mass production of semiconductor catalytic materials with interfacial heterostructures and in-situ coupling cocatalysts. The main results are as follows. The g-C _ 3N _ 4 / MoS _ 2 / go was prepared by a simple sonochemical method. The ultrathin MoS2 and go nanocrystals in the ternary composite nanomaterials have greatly improved the absorption properties of visible light. Further more, the photogenerated electrons. MoS2 nanocrystals were coupled with go and graphite to form two kinds of P-N heterojunctions at the interfaces of g-C _ 3N _ 4 / Mo _ 2 and g-C _ 3N _ 4 / go. The space charge layer produced by these heterojunctions not only effectively increases the photoelectron yield, but also increases the transfer and separation of electron hole pairs, effectively prolongs the lifetime of photogenerated electron hole pairs. Ultrathin MoS2 and go nanocrystals are high mobility electron transfer mediums, which further promote the transfer of photogenerated electron holes to g-C _ 3N _ 4 / Mo _ 2 and g-C _ 3N _ 4 / go interfaces. The experimental results show that the transient photocurrent intensity of the synthesized ternary sample g-C3N4 / MoS2 / go is 1.8 times that of the pure g-C3N4 sample, and the photocatalytic efficiency of degradation of RhB solution is 2.3 times of that of the pure g-C3N4 sample. The results show that g-C _ 3N _ 4 / MoS _ 2 / go has better photochemical properties and photocatalytic properties than other related contrast materials in visible light.) the multifunctional modification of AgNO3 is used in melamine thermal condensation. One-step synthesis of a porous ternary composite nano-material, g-C _ 3N _ 4 / Mo _ 2 / Ag. Agno _ 3, composed of g-C _ 3N _ 4 / Mo _ 2 / Ag. Agno _ 3, as an additional soft template for self-assembly of melamine during thermal condensation of melamine. Thin g-C _ 3N _ 4 nanocrystals and porous structures, The nanoscale Mott-Schottky effect produced by self-assembly coupling between Ag and g-C _ 3N _ 4 nanoparticles not only provides an effective channel for charge transfer, but also for separation. Moreover, the energy band of g-C _ 3N _ 4 nanochip was adjusted, and the energy band structure of g-C _ 3N _ 4 nanochip had synergistic effect. The transfer and separation of photogenerated electron holes at the interface of two-dimensional g-C _ 3N _ 4 / Mo _ S _ 2 heterojunction were accelerated. The ternary composite nanomaterials, g-C _ 3N _ 4 / Mo _ S _ 2 / Ag, synthesized by this method, were compared with other related contrast materials under visible light irradiation. The transient photocurrent intensity is about 3 times of that of the pure g-C _ 3N _ 4 sample, and the photocatalytic efficiency of the Rh _ B solution is 3.8 times that of the pure g-C _ 3N _ 4 sample. The photochemical and photocatalytic properties of the sample are greatly improved.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ127.11;TB33

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本文編號：1555033