氢气以其燃烧值高、产物无污染和利用形式多样等诸多优点而广受关注，被认为是理想的替代化石燃料的清洁能源载体。电催化水裂解利用可再生能源获得的电能分解水产生氢气，是极具前景的、绿色的制氢技术。然而，由于其反应动力学迟缓，大部分电催化反应都需要贵金属作为催化剂。受限于贵金属价格昂贵且储量少，人们亟需开发新型廉价的非贵金属电催化剂。尽管相关研究取得一定进展，但大多数已知的电催化剂依旧存在催化活性低的、稳定性不足等问题。过渡金属硼化物具有较高的导电能力，同时由于硼元素的掺入使其具有很好的抗腐蚀性，是一类潜在的新型水裂解电催化剂。尽管过渡金属硼化物在电催化水裂解方面具有诸多优势，但其合成始终较困难，通常需要复杂且昂贵的方法，加之目前对此类新型材料的催化机制认识不足，都在一定程度上阻碍其发展。针对以上问题，本论文通过固相渗硼，熔融盐辅助以及异质金属原子掺杂等合成策略，开发制备了一系列过渡金属硼化物电催化水裂解催化剂，实现了其在水裂解反应中高本征催化活性上的突破。通过对催化活性相的分析，阐释了过渡金属硼化物中特殊的晶体结构、电子结构与催化性能之间的内在联系。主要研究内容如下： 一、电催化水裂解析氧半反应由于反应能垒高，动力学缓慢，致使整体电催化能源转换效率低。尽管人们在水裂解析氧反应催化剂方面进行了许多努力，但几乎所有已知电催化剂的本征催化活性较低，开发高本征活性电催化剂仍是一个巨大的挑战。我们采用一种简单易操作的固相渗硼合成策略，将商业上常用的金属片(如Ni、Co、Fe、NiFe合金和304不锈钢)成功转化为高效、稳定、耐腐蚀的廉价电催化材料。硼化处理后的金属片在碱性条件下的催化活性比相应的金属片高出约一个数量级，同时显著增强了它们的电催化稳定性。经电化学测试并结合密度泛函理论计算，我们认为金属硼化物表面原位形成的超薄(2-5 nm)、含偏硼酸根的羟基氧化物薄膜使催化活性相。特别是，经过硼化处理后的NiFe合金片，具有极高的本征催化活性(过电位约309 mV)，同时，可以保持3000 h以上稳定工作。此外，经硼化处理后的304不锈钢在30％KOH溶液中，500 mA ㎝⁻²的强碱性、大电流密度模拟商业级的测试条件下，依然展现了良好的催化活性与催化稳定性。该工作说明固相渗硼法作为一种有效的金属硼化物合成策略不仅可以提高材料的催化活性，显著增强其催化稳定性和耐腐蚀性，更是为合理设计先进的催化剂开辟了一条新的途径。 二、合成金属硼化物通常需要跨越高的能量势垒，一般需要经历极端条件(高温、高压)或长时间的反应过程。熔融盐辅助合成策略可通过熔融盐的加入优化金属硼化物的合成条件，使金属硼化物在相对温和条件下的合成成为可能。我们通过熔融盐辅助方法成功地合成了11种过渡金属二硼化物，所合成的一系列过渡金属二硼化物其结构存在极大相似性。我们系统地研究了10种含平面“硼烯”亚结构单元的非贵金属二硼化物的电催化水裂解性能。我们发现所测试的同周期非贵金属二硼化物催化剂的酸性催化活性存在一定的周期性规律即VI B族>V B族>IV B族，这与理论计算结果相一致。我们对酸性和碱性条件下系列非贵金属二硼化物的活性进行筛选，确定了VB₂、MoB₂和WB₂是潜在的高效酸性电催化剂，而WB₂在碱性高效稳定电催化剂的筛选中表现出优异的性能。该工作增进了对过渡金属二硼化物催化材料的认识，同时通过合理测试方法筛选出具备优异催化性能的潜在电催化水裂解催化剂。 三、与在酸性介质中相比，大多数催化剂在碱性介质中催化活性较低，需要额外的能量进行水的解离为后续反应提供氢质子。异质金属原子掺杂是调节表面电子结构，活化反应势垒，提高催化活性的有效方法之一。我们通过Ni掺杂的合成策略，调控了WB₂表面电子和原子结构，制备出碱性条件下具有高本征催化活性的新型电催化水裂解材料。在电流密度达到10 mA㎝⁻¹时，所需过电位为98 mV，并可稳定工作100 h。相较于金属或金属合金催化剂，Ni掺杂的WB₂有效的降低了水解离的动力学势垒，促进了水的解离吸附速率。同时，Ni原子的引入诱导产生了大量的晶格结构的扭曲，使其表面原子具有更高的晶格能，从而提高了催化位点的本征活性。结合理论计算，表明Ni的引入降低了B与金属原子间的电荷转移，进而改变了B层原子局域电子结构，优化氢的吸附自由能，提高了整体催化反应性能。 关键词 电催化水裂解，过渡金属硼化物，合成策略，本征催化活性，电子结构

 Hydrogen has attracted much attention because of its high combustion value, nonpolluting products and various forms of utilization. It is an ideal clean energy carrier to replace fossil fuels. Electrocatalytic water splitting is a promising, green technology which uses electricity derived from renewable energy to decompose water to produce hydrogen. However, due to the slow reaction kinetics, most electrocatalytic reactions require precious metals as catalysts. Limited by the high price and low reserves of precious metals, there is an urgent need to develop new non-precious metal electrocatalysts. Despite some progress in related research, most electrocatalysts still have to suffer low catalytic activity and insufficient stability. Transition metal borides generally have high electrical conductivity, moreover, they have good corrosion resistance due to the incorporation of boron. It is a potential new type of water splitting electrocatalyst. Although transition metal borides have many benefits in electrocatalytic water splitting, their synthesis has always been difficult which requires complicated and expensive methods. In addition, the current lack of understanding of the catalytic mechanism of these materials has hindered their development to some extent. Aiming at the above problems, this thesis developed a series of transition metal boride electrocatalytic water splitting catalysts through pack boronizing, molten salt assistation and heterogeneous metal atom doping to achieve high intrinsic catalysis in water splitting reaction. The intrinsic relationship between special crystal structure, electronic structure and catalytic properties of transition metal borides is illustrated by the analysis of their catalytically active phase structures. The three main parts of this thesis including: Firstly, the OER is a kinetically sluggish reaction which makes the low energy conversion efficiency of the overall electrocatalytic reaction. Despite many efforts are made in OER electrocatalysts, as we know, almost all the electrocatalysts still have low intrinsic catalytic activity, and the development of high intrinsic active electrocatalysts remains a significant challenge. We use a simple and easy-to-operate pack boronizing synthesis strategy to successfully convert commercially metal sheets (such as Ni, Co, Fe, NiFe Alloy and SUS 304) into efficient, stable and corrosion-resistant inexpensive electrocatalytic materials. The catalytic activity of the boronized metal sheets under alkaline conditions are about an order of magnitude higher than that of the corresponding metal sheets, while significantly enhancing their electrocatalytic stability. We reveal that these metal borides exhibit unique self-functionalized behaviour during electrocatalysis by in situ growth of ultrathin (2-5 nm), metaborate-containing oxyhydroxide thin films on the surface as a highly active catalytic phase. In particularly, the boronized NiFe Alloy sheet exhibits an extremely high intrinsic catalytic activity (overpotential at ～309 mV), and at the same time, it can maintain stable operation for more than 3000 hours. More attractively, the boronized NiFe Alloy and SUS 304 present greatly enhanced and excellent catalytic stability and corrosion resistance during electrocatalysis in 30% KOH solution at large current density which simulated commercial conditions. This work shows that pack boronizing as an effective metal boride synthesis strategy can not only improve the catalytic activity of the material, but also significantly enhance its catalytic stability and corrosion resistance. It also opens up a new dimension for the rational design of advanced catalysts. Secondly, synthesis of metal borides usually needs to conquer a high energy barrier, which generally requiring extreme conditions (high temperature, high pressure) or long reaction processes. The molten salt-assisted synthesis strategy can optimize the synthesis conditions of the metal boride. By adding molten salt, it makes the reaction possibly occur under relatively mild conditions. We successfully synthesized 11 transition metal diborides by molten salt-assisted method. The structure of a series of transition metal diborides has great similarity. Combining theoretical calculations and electrochemical measurements, we systematically studied the HER performance of 10 non-precious metal diborides which containing "borane" subunit structures. We found that the acidic HER activity of the nonprecious metal diborides have a certain periodicity, e.g., VI B>V B>IV B, which is consistent with the theoretical calculation results. At the same time, we measured the activity of a series of non-precious metal diboride catalysts under acidic and basic conditions, and determined that VB2, M0B2 and WB2 are potential high-efficiency acidic electrocatalysts, while WB2 behaves high-efficiency and stable HER performance in alkaline condition. This research has further deepened our understanding of metal diboride catalytic materials, and successfully screened potential HER electrocatalysts with excellent performance through reasonable methods. Thirdly, most electrocatalysts have lower activity in alkaline media than acidic, because it needs additional energy to dissociate water to provide more H⁺ for subsequent reactions under alkaline condition. Heterogeneous metal atom doping is one of effective methods to adjust surface electronic structure, activate reaction barrier, and improve catalytic activity. We have controlled the surface electron and atomic structure of WB₂ through the synthesis strategy of Ni doping, and prepared a new HER electrocatalytic material with high intrinsic catalytic activity in alkaline media. When the current density reaches 10 mA ㎝⁻¹, the required overpotential is 98 mV and it can catalyze stably for 100 h. Compared with other metals or alloys, Ni-doped WB₂ effectively reduces the kinetic barrier of hydrolysis and promotes the dissociation adsorption rate of water. At the same time, the incorporation of Ni atoms can induce a large amount of lattice distortion, which makes the surface atoms have higher lattice energy, thereby increasing the intrinsic activity of the catalytic sites. Combined with theoretical calculations, it is shown that Ni reduces the charge transfer between B and metal atoms, which changes the local electronic structure of B-layer atom, optimizes the adsorption free energy of hydrogen, and improves the HER performance. Keywords: Electrocatalytic water splitting, transition metal borides, synthetic strategies, intrinsic catalytic activity, electronic structure.