虽然团簇和原子级分散材料具有提高原子利用率、提升催化活性选择性和降低催化剂成本等优点，但是团簇和原子级分散材料的高自由能使其在制备和使用过程中容易发生团簇，进而限制了其研究和应用。此外，高活性、高选择性和高稳定性的电催化剂，铃木反应催化剂和苯酚加氢催化剂一直不仅是催化研究的热点还是制备清洁能源和精细化学品的关键。本论文设计了多种新方法，研究了液相中的成核和生长的控制方法与机理，探索了原子级分散催化剂和团簇催化剂的制备方法、形成机理、催化性能和对应的催化机理。本论文的主要研究内容如下：1、设计了冰相光还原、缓释化学、超低温光化学和溶液的快速热退火等方法。其中，冰相光还原通过冰来抑制产物的扩散进而抑制成核过程，且只适用于金属离子能够被光还原的原子级分散材料的制备。缓释化学通过调节反应物的浓度来抑制成核过程的，虽然该方法能够成功制备11种原子级分散的材料，但反应物的低浓度限制了其高载量样品的获得。超低温光化学通过超低的反应温度调节了反应的动力学和热力学，进而有效抑制成核过程。该方法可以很容易地从光化学扩展到大多数化学反应中，例如复分解反应和置换反应等。溶液的快速热退火方法是通过调控金属离子的分散进而抑制成核的，其适用于金属离子能够被热分解还原的反应。这些方法为重新设计湿化学方法的反应动力学等提供了通用的方法。2、研究了团簇和原子级分散材料的催化性能和机理。原子级分散的Pt催化剂具有高效的电化学催化析氢活性和稳定性，其具有在100 mA cm-2电流密度下的过电势只有55 mV、26 mV dec-1的Tafel斜率和长时间的稳定性。这种原子级分散的Pt催化剂的电催化性能优于最先进的商业Pt/C催化剂。负载在氮掺杂介孔碳上的高度分散的Pd原子/团簇催化剂不仅在氯苯的铃木反应中显著提高的催化活性(产率为95%)、较高的选择性 (100%)和优秀的稳定性(10次循环稳定性测试后催化活性几乎没有衰减)，还在更多的带有不同官能团和卤族元素的底物范围内也表现出了优越的产率和良好的选择性(>70%)。首次实现了室温常压下的100%转化率和100%KA油选择性的苯酚加氢性能，并证明在Pt/TiO2催化剂上发生的室温常压的苯酚加氢是一个级联反应。这项工作不仅为在室温常压下工业化生产KA油开辟一条新途径，还为理解加氢的催化机理提供见解。

Cluster and atomically dispersed materials have the advantages of improving atomic utilization, promoting catalytic activity and selectivity, and reducing catalyst cost. However, the high free energies of cluster and atomically dispersed materials result in their agglomation of clusters and atoms in the process of synthese and applications, which further limits their research and applications. Moreover, superior catalysts with high selectivity and excellent stability for electrocatalysis, Suzuki reactions and phenol hydrogenation have been not only the hot topic of catalysis but also the key to the syntheses of clean energy and fine chemicals. In this paper, the controland mechanism of nucleation and growth in the solution was studied via iced photochemical reduction, slow release process and ultralow-temperature method, etc. Furthermore, the syntheses of atomically dispersed metal materials and clusters, their formation mechanism, their catalytic performance and corresponding catalytic mechanism were investigated. My major research and their results of this paper are shown bolow.1. We designed iced photochemical reduction, slow release process, ultralow-temperature photochemical methods, and solution rapid annealing process to prepare atomically dispersed metal materials. Among them, ice photochemical reduction could inhibit the diffusion of products via the presence of ice lattice, and thus control the nucleation process, which is only applicable to the syntheses of atomically dispersed materials whose metal ions could be photo reduced. Regulating the concentration of reactants via ice melting process, nuclei process was prevented in slow-release chemistry. Although this slow-release method was successful in preparing 11 atomically dispersed metal materials, the demand of low concentration limited the availability of high-loading atomically dispersed metal samples. Ultralow-temperature photochemical method could adjust the kinetics and thermodynamics of the reaction through the ultralow temperature, and thus effectively inhibit the nuclei process and preparing atomically dispersed metal materials. This method could be easily extended from photochemistry to most chemical reactions, such as double decomposition and displacement reactions, etc. The solution rapid annealing process could efficiently control the dispersion of metal ions and then inhibit their nucleation to synthesize atomically dispersed metal materials. These methods provide general methods for redesigning the reaction kinetics of wet chemistry.2、Atomically dispersed Pt on nitrogen-doped mesoporous carbon exhibited efficient catalytic activity for electrochemical hydrogen evolution reactions, with an overpotential of only 55 mV at a current density of 100 mA cm-2, low Tafel slope of 26 mV dec-1 and long-time durability superior to the state-of-the-art platinum/carbon catalysts. Moreover, nitrogen-doped mesoporous carbon supported Pd single-atom/cluster catalyst exhibited significantly boosted activity (100% selectivity and 95% yield) and excellent stability (almost no decay in activity after 10 reuse cycles) for the Suzuki coupling reactions of chlorobenzenes, together with superior yield and excellent selectivity in the fields of the board scope of the reactants for Suzuki coupling reactions. The 100% conversion with 100% selectivity of KA oils in phenol hydrogenation at room temperature and ambient pressure was achieved for the first time. It confirmed that the phenol hydrogenation over Pt/TiO2 catalyst was a cascade reaction. This work opens a new way to industrial production of diverse KA oils at room temperature and ambient pressure and provides insights in understanding the catalytic mechanism of hydrogenation of phenol.