面向海水电化学释氢的多位点协同阵列电极的设计构筑和作用机制

Hydrogen is an extremely important energy carrier due to its high calorific value, multiple sources, various utilization forms and pollution-free reaction products. Electrolysis of water to produce hydrogen is a simple method with high purity, which can be used in the field of transportation based on hydrogen and oxygen fuel cells. In view of the key problems exist in seawater electrolysis, such as high overpotential and medium reaction dynamics, this project is solely based on the long-term accumulation of applicant in surface and interface regulation improved the catalytic capacity, puting forward a simple and efficient new strategy for preparation of multiple sites synergistic catalytic array electrode, using the integration of strong adsorption H* and OH- active ingredients. Therefore, the H-OH bond breaking is no longer a limiting step for water splitting under neutral conditions. Combined with theoretical calculation, rational screening of the active sites at the early stage and in-depth understanding of catalytic mechanism at the later stage were carried out to realize the controllable construction of multiple sites coordinated seawater electrochemical hydrogen evolution electrode, so as to obtain cheap non-noble metal based electrode with high activity and stability. On this basis, the influence of the proportion of different sites and the parameters of preparation process on the catalytic performance were studied in more detail, and the structure-activity relationship between the multiple cooperative catalytic components and the electrochemical efficiency was established. Through the implementation of this project, it is expected to provide theoretical and practical foundation of the electrode with high efficiency for seawater hydrogen evolution in energy conversion and storage.

氢气具有热值高来源广、利用形式多、反应产物无污染等优点是极其重要的能源载体。电解水产生氢气方法简单，产生的氢纯度高，可通过氢氧燃料电池高效的用于交通运输领域。针对目前海水释氢过程过电位高，水分解催化动力不足等关键问题，本项目基于申请人在表界面调控提升电极催化功效研究的基础上，提出一种简单、高效制备多位点协同催化阵列电极的新方法，用对H*，OH-具有强吸附能力的活性成分进行集成，使得H-OH键断裂不再是中性条件水分裂的限制步骤。结合理论计算进行前期活性位点的理性筛选和后期对催化机理的深入认识，实现对多位点协同海水电化学释氢电极的可控构筑，从而得到高活性稳定性的廉价非贵金属基电极。在此基础上，深入研究不同作用位点比例，催化剂制备过程参数等对催化性能的影响，建立多位点协同催化成分-电化学功效之间的构效关系，为具有高效海水析氢性能电极在能量转换存储中的应用奠定理论和实践基础。

双碳目标下需要对能源利用形式做优化调整。氢气具有多种优点是极其重要的能源载体。电催化驱动的分解水产生绿氢方法简单，是有前途的制氢策略。目前电解水制氢过电位高，水分解催化动力不足是需要解决的问题。项目基于提出的多位点协同催化思想，构筑了多种界面协同催化电极（多组分界面；载体/催化中心界面），利用界面处的电子相互作用，调控金属中心的电子荷电状态，优化反应中间物的吸附脱附过程。主要完成了下面几个方面的工作：(1) 制备的硒化物/镍铁氢氧化物、磷化物/氢氧化物、硫化物/氢氧化物等电极在水分解过程显示出了高的催化活性（232mV过电势可产生100mA cm-2）和稳定性(100mA cm-2可以稳定100小时)，计算结果表明多组分界面有利于*OOH中间物的产生。(2)利用引入外来协同原子（Cr, V等）优化金属硫化物和双金属氢氧化物等催化中心的电子密度，加速催化过程界面的重构和活性提升。Cr引入到NiZn LDH催化剂中，调控了位点的电子密度，催化剂中部分金属元素移除，最终表面重构出羟基氧化物作为真实的催化中心。(3)构筑了多种载体/催化剂强耦合界面，调控催化中心的电子密度，提升催化过程的电子传输能力。此外，电极的阵列化设计极大加速了物质传输过程，保证了电解液渗透和气体扩散。本项目较系统地研究了多组分界面在催化过程中的协同作用规律，建立了多位点协同电极制备-组成-催化性能之间的内在规律，为多位点协同电极在电解海水释氢应用提供了基础。.本工作已在Fuel, chem commun, International Journal of Hydrogen Energy等国际SCI期刊发表论文16篇，授权发明专利1项。