基于纳米卤化银修饰对Ag3PO4太阳能光催化稳定性能的研究

Taking a consideration of the present situation of energy shortage and environment pollution in China, this project focuses on the water environment pollution caused by difficult degradable organic pollutants in the water, as well as aims to use the renewable energy-solar photocatalytic degradation of persistent toxic organic pollutants in water. Then nano silver halides modified Ag3PO4 photocatalytic materials which is more efficient, stable and sensitive to solar light will be designed and synthesized. Studied in detail on the basis of the catalyst stability and combined with the characterization of catalytic materials, the micro-structural characteristics such as the absorption characteristics, crystal structure and surface condition of nano silver halides modified Ag3PO4 photocatalytic materials will be analyzed in depth. Furthermore, the scientific mechanism of the nano silver halides that helps to improve the stability of silver phosphate under solar light will be revealed and the preparation Technology of nano silver halides modified Ag3PO4 will be formed, which provide a theoretical basis for the purifications of persistent organic pollutants in environmental (gas, liquid and solid) systems under natural light.

该项目从我国能源紧缺和环境污染的现状出发，围绕有毒且难降解有机污染物所引起的水环境污染问题，以可利用可再生能源- - 太阳能光催化降解水中持久性有毒有机污染物为目标，设计和合成高效、稳定、可吸收太阳光的纳米卤化银修饰Ag3PO4光催化材料。在详尽研究催化剂稳定性的基础上，结合催化材料的表征深入分析纳米卤化银修饰Ag3PO4材料的吸光特性、晶体结构、表面状态等微观结构特征，并与宏观有机物降解的稳定性相关联，揭示纳米卤化银修饰对提高Ag3PO4太阳能光催化稳定性的科学机理，形成纳米卤化银修饰Ag3PO4光催化材料的制备技术，为环境（气、固、液）中持久性有毒有机污染物的自然光净化提供理论依据。

本研究目标在于通过卤化银的修饰以期提高磷酸银的光催化稳定性，从而可使磷酸银充分利用太阳光进行光催化反应，并将其应用于水中持久性有机污染物的净化中。首先利用沉淀法、沉淀置换法及水热合成法等技术制备了AgCl@Ag3PO4、AgBr@Ag3PO4 与AgI@Ag3PO4一系列纳米结构复合光催化剂，并发现通过有机半导体C3N4对Ag3PO4进行修饰可显著提高磷酸银的光催化活性及稳定性；采用现代光谱表征技术详细分析了各种催化剂的晶体结构、吸光特点、表面形态等微观物理结构特征，并深入分析了光催化剂的结构与性能和稳定性之间的内在关系。研究表明：（1）AgCl修饰可使复合催化剂的带隙能减小、并与Ag0形成表面等离子共振效应而提高催化剂的光催化活性；（2）AgBr修饰有助于形成表面等离子体共振效应、e--h+的分离及价带上h+氧化能力的提高而使Ag3PO4的光催化活性及稳定性显著提高；（3）虽然AgI修饰可在一定程度上提高磷酸银的光催化活性，但终因AgI自身的光腐蚀性很大而难以提高磷酸银的稳定性。新型、高效、稳定的光催化剂仍在研制中，这对光催化高级氧化技术的实用化非常重要。