贵金属-半导体复合催化剂在不同组分之间会产生强相互耦合作用，不仅能够调控、增强各组分原有的性质，而且常伴有其它一些新特性的出现，为更好满足各类催化反应需求提供了更多的可能。然而这类催化剂具有更加复杂的组分和结构，导致催化剂的主要活性位结构研究更加困难，难以有效建立催化剂的构效关系。同时，这类催化剂中的贵金属一般以聚集态的颗粒存在，导致贵金属的利用率不高以及不同组分间的耦合作用不充分等问题。本论文针对当前这类复合催化剂存在的难题，分别构建了Pd／非晶Fe₂O₃的核／壳型复合纳米催化剂，以及空心的Pt，Pd单原子非晶催化剂，并系统研究了这些催化剂的电催化反应性能。本论文有望对复合催化剂的调控合成、构效关系研究以及开发新型复合催化剂提供借鉴。 设计、制备了Pd／非晶Fe₂O₃的核／壳型复合催化剂，实现了非晶Fe₂O₃对Pd核纳米晶的可控包覆。通过研究不同包覆程度的Pd／非晶Fe₂O₃复合催化剂对电催化甲醇氧化的性能影响，发现催化活性完全取决于暴露界面的周长。同步辐射的进一步表征及DFT理论计算，表明界面的Pd-Fe结构即为主要催化活性位，并进一步阐明了具体的催化机理。而且该活性位结构对乙醇的电催化氧化也具有超高活性。当催化剂为半包覆的核／壳结构时，拥有的有效界面活性位数量最多，对甲醇和乙醇的电催化氧化活性远高于目前文献所报道的Pd基催化剂。 发展了离子交换、还原及进一步腐蚀的策略，制备了非晶、空心的Pt₁CuS〓催化剂。表征证实贵金属Pt呈单原子状态，即实现了贵金属Pt与硫化亚铜的原子级复合。在电催化O₂还原的过程中，该催化剂表现出了电催化合成H₂O₂的高活性和高选择性。双氧水的产率为546±30 mol ㎏〓，h⁻¹，高达目前最佳单原子催化剂的44倍，也是目前最佳热催化剂活性的4倍。 利用我们提出的离子交换、还原及进一步腐蚀的策略，制备了单原子Pd₁-CuS〓催化剂。表征证实催化剂中不含Pd-Pd键，达到贵金属与半导体的最大复合程度。在电催化有机合成过程中，该催化剂对C-H／S-H的脱氢偶联表现出了高活性。达到目前文献报道的体相Pt电极具有的催化活性。当催化体系中存在质子接收剂(硝基苯)时，则反应的转化率明显进一步提高(>95％)，同时该催化剂能够直接催化硝基苯还原成苯胺。 关键词：复合催化剂；贵金属；非晶；单原子；催化

 Noble metal-semiconductor nanocomposite catalysts can produce strong mutual coupling between different components, which can not only regulate and enhance the original properties of each component, but also generate some new characteristics. This provides possibilities for better response to the needs of various catalytic reactions. However, such catalysts have more complex compositions and structures, making it more difficult to investigate the active site structure of the catalysts, and it seems impossible to effectively establish the structure-activity relationship of the catalyst. Moreover, the noble metals in these catalysts typically exist as aggregated particles, resulting in low utilization of the noble metals and insufficient coupling between different components. In this paper, for the existing problems of such nanocomposite catalysts, the core/shell structure of Pd/amorphous Fe₂O₃ and the amorphous, hollow Pt and Pd singleatom catalysts were constructed, and their electrocatalytic performance was systematically explored. This paper was expected to provide a basis for studies on the controllable synthesis, and structure-activity relationship of nanocomposite catalysts, as well as for the development of novel composite catalysts. The core/shell nanocomposite catalysts of Pd/amorphous Fe₂O₃ were designed and prepared, and a controlled coating of amorphous Fe₂O₃ on Pd core nanocrystals was achieved. The effect of nanocomposite catalysts of Pd/amorphous Fe₂O₃ with varying coating degrees on the performance of electrocatalytic methanol oxidation was investigated, and it was found that the catalytic activity was completely dependent on the perimeter of the exposed interface. The further characterization of synchrotron radiation and DFT theoretical calculations indicated that the Pd-Fe structure on the interface was the main catalytic active site, and the specific catalytic mechanism was further clarified. In addition, the active site structure also had extremely high activity for the electrocatalytic oxidation of ethanol. When the catalyst had a semi-coated core/shell structure, it had the largest number of active sites on the effective interface. The electrocatalytic oxidation activities for methanol and ethanol were much higher than that of the reported Pd-based catalysts. The strategies of ion exchange, reduction and further corrosion were developed, and amorphous, hollow Pt〓-CuS〓 catalysts were prepared. The characterization confirmed that the noble metal Pt was in the single-atom state, that is, the atomic-level composition of noble metal Pt and cuprous sulfide was achieved. During the electrocatalytic reduction of O₂, the catalyst exhibited high activity and selectivity in the electrocatalytic synthesis of H₂O₂. The yield of hydrogen peroxide was 546±30 mol ㎏〓 h⁻¹, which was up to 44 times that of the currently best single-atom catalyst and four times that of the currently best thermal catalyst. Amorphous, hollow Pd₁-CuS〓 catalysts were prepared following the strategies of ion exchange, reduction and further corrosion. The characterization confirmed that the catalysts did not contain Pd-Pd bonds, reaching the maximum degree of compounding of noble metals and semiconductors. In the electrocatalytic organic synthesis process, the catalyst exhibited high activity in the dehydrogenation coupling of C-H/S-H, at a level equivalent to the catalytic activity of bulk-phase Pt electrodes reported. When the proton acceptor (nitrobenzene) was present in the catalysis system, the conversion of the reaction was significantly increased (>95%), and the catalyst could directly catalyze the reduction of nitrobenzene to aniline. Keywords: composite catalyst; noble metal; amorphous; single-atom; catalysis