摘 要
纳米金催化剂因其独特的物理化学性质和优异的催化性能，在环境治理、化工合成及能源转化等领域展现出广阔的应用前景，其中硝基苯还原反应作为典型的有机转化过程，是研究纳米金催化机理的重要模型反应。本研究旨在深入探讨纳米金催化的硝基苯还原反应机制，揭示其活性位点、反应路径及影响因素，为优化催化剂设计提供理论依据。通过制备不同尺寸与载体的纳米金催化剂，并结合原位红外光谱、X射线吸收精细结构谱及密度泛函理论计算等手段，系统分析了催化剂表面结构与反应中间体的相互作用。研究发现，纳米金颗粒的尺寸效应显著影响其电子结构与表面活性位点分布，较小尺寸的纳米金表现出更高的催化活性；同时，载体类型对催化剂稳定性及反应选择性具有重要调控作用。实验结果表明，硝基苯在纳米金表面首先发生吸附活化，随后经历氢化步骤生成中间产物羟基胺，最终转化为目标产物苯胺，整个反应过程中氢气解离吸附是关键步骤。此外，研究还揭示了反应条件如温度、压力及溶剂极性对催化性能的影响规律，并提出了一种基于界面电子转移机制的催化模型。本研究的创新点在于首次明确了纳米金催化硝基苯还原反应中活性位点的具体作用机制，建立了催化剂结构与催化性能之间的构效关系，为开发高效稳定的纳米金催化剂提供了新思路，同时为相关领域的基础研究与工业应用奠定了坚实的理论基础。
关键词：纳米金催化剂；硝基苯还原反应；活性位点；尺寸效应；载体作用
Abstract
Nanogold catalysts, owing to their unique physicochemical properties and superior catalytic performance, have demonstrated promising application prospects in environmental remediation, chemical synthesis, and energy conversion. Among these applications, the reduction of nitrobenzene, as a typical organic transformation process, serves as an important model reaction for investigating the catalytic mechanism of nanogold. This study aims to explore the mechanism of nanogold-catalyzed nitrobenzene reduction in depth, revealing its active sites, reaction pathways, and influencing factors to provide theoretical guidance for optimizing catalyst design. By preparing nanogold catalysts with different sizes and supports, and combining them with in-situ infrared spectroscopy, X-ray absorption fine structure spectroscopy, and density functional theory calculations, the interactions between the catalyst surface structure and reaction intermediates were systematically analyzed. It was found that the size effect of nanogold particles significantly influences their electronic structure and distribution of surface active sites, with smaller-sized nanogold exhibiting higher catalytic activity. Moreover, the type of support plays a crucial role in regulating the stability and selectivity of the catalyst. Experimental results indicate that nitrobenzene undergoes adsorption activation on the nanogold surface, followed by hydrogenation steps to generate hydroxylamine as an intermediate product, ultimately converting into the target product aniline; the dissociative adsorption of hydrogen is a key step throughout the reaction process. Additionally, this study elucidated the influence patterns of reaction conditions such as temperature, pressure, and solvent polarity on catalytic performance and proposed a catalytic model based on the interfacial electron transfer mechanism. The innovation of this research lies in the first explicit clarification of the specific action mechanism of active sites in the nanogold-catalyzed nitrobenzene reduction reaction, establishing the structure-property relationship between catalyst structure and catalytic performance, which provides new insights for developing highly efficient and stable nanogold catalysts and lays a solid theoretical foundation for fundamental research and industrial applications in related fields..
Key Words：Nano-Gold Catalyst；Nitrobenzene Reduction Reaction；Active Site；Size Effect；Support Role
目 录
摘 要 I
Abstract II
第1章 绪论 1
1.1 纳米金催化研究背景与意义 1
1.2 硝基苯还原反应的研究现状 1
1.3 本文研究方法概述 2
第2章 纳米金催化剂的制备与表征 3
2.1 纳米金催化剂的制备方法 3
2.2 催化剂的物理化学性质表征 3
2.3 纳米金催化剂稳定性分析 4
2.4 表征技术在催化剂研究中的应用 5
第3章 硝基苯还原反应动力学研究 6
3.1 反应动力学基础理论 6
3.1.1 动力学方程解析 6
3.1.2 反应速率常数测定 6
3.1.3 温度对反应速率的影响 7
3.1.4 催化剂负载量优化 7
3.2 纳米金催化的反应路径分析 7
3.2.1 中间产物检测方法 8
3.2.2 还原过程中的电子转移机制 8
3.2.3 表面活性位点的作用 8
3.2.4 反应条件对路径选择的影响 9
3.3 动力学模型的建立与验证 9
3.3.1 模型假设与构建方法 9
3.3.2 数据拟合与误差分析 10
3.3.3 实验结果与模型预测对比 10
3.3.4 模型适用范围探讨 10
第4章 纳米金催化机理的深入探讨 12
4.1 催化剂表面结构与活性关系 12
4.1.1 不同晶面的活性差异 12
4.1.2 表面缺陷对催化性能的影响 12
4.1.3 配体修饰的作用机制 13
4.1.4 粒径效应分析 13
4.2 反应过程中纳米金的动态行为 13
4.2.1 催化剂结构演变观察 14
4.2.2 表面重构现象研究 14
4.2.3 纳米颗粒聚集效应分析 14
4.2.4 原位表征技术的应用 15
4.3 理论计算辅助机理研究 15
4.3.1 密度泛函理论 16
4.3.2 吸附能与反应能垒计算 16
4.3.3 关键中间体稳定性分析 16
4.3.4 理论预测与实验结果对比 17
结 论 17
参考文献 19
致 谢 20
