复合型金属纳米空心材料的制备及其优异光催化降解特性研究

The hybrid metal porous nano-cages with a controllable interior space and a distinctive porous shell have received increasing attention in recent years. The unique objects are characterized as fine nano-particles with lower densities, larger specific surface area, and higher permeability, possessing highly applications in super sensing (light, electron, magnetism) because of their excellent absorption in near-infrared and photo-thermal conversion properties. The properties of the hybrid nano-cages are strongly dependent on their porous surfaces and hollow interiors,. In this project, the hybrid metal nano-cages with hollow interiors will be devised through Galvanic Replacement Reaction (GRR) by pulsed laser ablation of Ag target in metal ion (HAuCl4, Na2PtCl4) solutions. The porous nano-cages with a controllable interior cavity should be synthesized during the replacement reaction between metal nano-particles and activated solution due to photo-thermal heating by pulses laser irradiation. The parameters of laser ablation/irradiation and solute concentration will play critical roles for controlling the replacement reaction degree and rate. Then, UV-Vis-NIR optical absorption spectrum of Ag/Au and Ag/Pt nano-cages will be used to investigate the strong and super wide adsorption of nano-cages in NIR. The profile of the NIR absorption is characterized by the continuous red shift, broadened and intensive spectral lines. The obtained hybrid Ag/Au and Ag/Pt nano-cages with superior improved photo-catalytic activity and excellent stability in photo-catalytic reduction will be investigated in this work. This project provides a new paradigm to obtain hollow like nano-cage directly from bulk materials and inspires deeper investigations for generation more complex structures by this strategy. The relevant physical mechanism obtained from theoretical models and experiments have significant implications for getting an insight into the properties of the porous nano-cages, offering the basis for further development of reliable applications with efficiency and defined purposes.

复合型金属纳米空心材料的独特壳层构型产生奇特的微观“包裹”效应，使其在超灵敏的光、电、磁、传感及吸附等方面呈现出优异特性。本项目充分发挥物理与化学合成优势，利用脉冲激光在金属离子（HAuCl4, Na2PtCl4）溶液中烧蚀Ag靶材，辐照诱导伽伐尼置换反应，实现可控合成Ag/Au和Ag/Pt纳米空心材料。系统分析Ag/Au和Ag/Pt纳米空心材料的近红外强吸收特性，深入研究合成材料的光催化性能与单分散的纳米空心结构的内在关联。采用电化学系统测试可见光照射下与空心Ag/Au和Ag/Pt纳米光催化剂光电极的循环伏安曲线。分析相关数据，在微观层次上，研究光生电子-空穴的激发、分离、复合及传输在光催化反应中的规律，揭示催化剂性能与结构之间的关系，阐明光催化还原转化 CO2及光催化降解甲基橙、亚甲基蓝等染料分子的机理。本项目研究成果将为后续研究该新型材料的众多优异特性奠定实验和理论基础。

本项目重点探索了激光液相辐照策略，通过激光有效激发二维材料h-BN、GO前驱体产生的活跃电子作为绿色高效的还原剂，实现了周围溶液中金属离子的有效还原，使得贵金属纳米颗粒成功负载生长在化学性质稳定的二维材料表面。基于此，可控合成了多种形态的金属基复合构型，如h-BN/Au、h-BN/CuAg、h-BN/PtPd、GO/Au等纳米复合材料，分别探索了其优异的表面增强拉曼散射及电催化性能。在制备过程中可以通过调节激光辐照时间调控复合构型中金属的含量，对其性能进行优化，并探究了优异性能产生的内在物理机理，为构建高性能的传感探测器与催化剂提供新思路。此外，基于GO表面丰富的含氧官能团，我们进行了有意义的扩展研究，在乙醇辅助作用下调控构建出GO/PtPd复合材料，进一步探索了GO/PtPd复合材料的电催化性能，对于多功能复合材料的前沿交叉研究具有重要意义。