【作者】 王波；

【导师】 刘斌； 李妙鱼；

【作者基本信息】 山西大学 ， 无机化学， 2021， 硕士

【摘要】 近年来,环境污染对人类文明发展造成了严重威胁,通过光催化技术来降解有害物质被视为解决污染的重要手段。传统的半导体光催化材料TiO₂仅吸收紫外线,对太阳光的利用率低,不能有效降解污染物。所以,需要研发新型光催化剂,扩大其对可见光的响应范围,提高光催化效率。富氮的石墨相g-C₃N₄由于其稳定性和吸引人的电子结构而成为研究最广的材料之一,而C₃N₅作为一种新型无金属半导体,拥有与g-C₃N₄不同的CN骨架结构,呈现了较高的热力学稳定性和优异的电子性能,同时具有小的带隙能（1.76 eV）。为了提高C₃N₅的光催化效率,本文研究了C₃N₅基复合材料在模拟太阳光照下对亚甲基蓝（MB）的降解和产氢性能,具体内容如下:（1）以3-氨基-1,2,4-三唑（3-AT）和乙酸锌为前体材料,采用研磨法、水热法和高温煅烧法三者结合的方式制备了一系列低成本、环境友好型的ZnO/C₃N₅新型光催化纳米复合材料。然后通过一系列手段对它们的结构、光吸收波长范围和电荷输运特性等进行了表征。ZnO/C₃N₅间良好的界面接触和较强的相互作用,拓宽了太阳光的吸收范围,改善了光生电子-空穴对的分离和电荷迁移率,对亚甲基蓝（MB）染料在可见光下有良好的降解效果。实验结果表明在50分钟内降解效率可达90%以上,且六次循环利用后催化性能基本不变,远优于纯C₃N₅光催化材料。（2）将硼酸作为硼源,采用一种简便的高温煅烧法制备了一系列低成本的非金属B掺杂C₃N₅的光催化剂,通过一系列手段研究了B掺杂C₃N₅光催化剂的微观形态结构、光学和电学性质。光催化降解亚甲基蓝实验结果显示,B掺杂C₃N₅的光催化降解效率在60分钟内可达90%,且六次循环利用后基本不变;光催化分解水产氢实验结果显示,产氢量可达1285μmol,约为未掺杂C₃N₅的2.6倍。研究发现,B原子的引入促进了C₃N₅光诱导载流子的分离,改变了C₃N₅的能带位置,使得光催化降解和产氢性能都明显提高,而且具有良好的循环稳定性。因此,该研究所制备的光催化材料及其制备方法为开发更多带隙可调的新型C₃N₅基稳定光催化复合材料提供了潜在的应用前景。更多还原

【Abstract】 In recent years,environmental pollution has posed a serious threat to the development of human civilization.Degrading harmful substances through photocatalytic technology is regarded as an important means to solve pollution.The traditional semiconductor photocatalytic material TiO₂ only absorbs ultraviolet light,has a low utilization rate of sunlight,and cannot effectively degrade pollutants.Therefore,it is necessary to develop a new type of photocatalyst,expand its response range to visible light,and improve the photocatalytic efficiency.The nitrogen-rich graphite phase g-C₃N₄ has become one of the most widely studied materials due to its stability and attractive electronic structure.As a new type of metal-free semiconductor,C₃N₅ has a CN framework structure different from g-C₃N₄.It has high thermodynamic stability and excellent electronic properties,while having a small band gap energy（1.76 eV）.In order to improve the photocatalytic efficiency of C₃N₅,this paper studied the degradation of methylene blue（MB）and hydrogen production performance of C₃N₅-based composite materials under simulated sunlight.The specific content is as follows:（1）A series of low-cost,eco-friendly and novel ZnO/C₃N₅ photocatalysis nanocomposites were prepared by grinding,hydrothermal and high-temperature calcination methods with 3-amino-1,2,4-triazole（3-AT）and zinc acetate as precursors.Then the morphology,structure and properties were verified by a series of methods.The good interface contact and strong interaction between ZnO/C₃N₅ broaden the absorption range of sunlight and improve the separation of photogenerated electron-hole pairs and the charge mobility,it showed a good degradation effect on methylene blue（MB）dye under visible light.The experimental results show that the degradation efficiency can reach more than 90%within 50 minutes,and the catalytic performance is basically unchanged after six cycles,which is far better than pure C₃N₅ photocatalytic materials.（2）Using boric acid as the boron source,a series of low-cost non-metal B-doped C₃N₅ photocatalysts were prepared by a simple high-temperature calcination method.Through a series of characterizations,the microstructure,optical and electrical properties of the B-doped C₃N₅ photocatalyst were studied.The experimental results of photocatalytic degradation of methylene blue show that the photocatalytic degradation efficiency of B-doped C₃N₅ can reach 90%within 60 minutes,and it is basically unchanged after six cycles.The experimental results of photocatalytic decomposition of water to produce hydrogen show that the amount of hydrogen production can reach 1285μmol,which is about 2.6 times that of undoped C₃N₅.The study found that the introduction of B atoms promoted the separation of C₃N₅ light-induced carriers,changed the energy band position of C₃N₅,and significantly improved the performance of photocatalytic degradation and hydrogen production,and had good cycle stability.Therefore,the photocatalytic materials and preparation methods prepared by the research institute provide potential application prospects for the development of more new C₃N₅-based stabilized photocatalytic composite materials with adjustable band gaps.更多还原