纳米多孔金属/氧化物复合电极材料可控构筑及其水氧化催化性能

Fast-growing demands for renewable energy have stimulated considerable interest in developing highly efficient energy conversion devices. Hydrogen is a clean and sustainable energy carrier that can be generated by water splitting via water-alkali electrolyzers and oxidized to release energy with the generation of water. The interconversion of water and hydrogen promises an environmental friendly perspective of energy storage/delivery without any carbon dioxide emissions, in particular, when the electrolysis process is powered by renewable energy sources, such as wind- or solar-based technologies. Relative to the hydrogen evolution reaction occurring at the cathode of water-alkali electrolyzers, the water oxidation (also called as oxygen evolution reaction) at the anode suffers from the sluggish kinetics and becomes the rate-limited reaction for the water splitting. Therefore, it is highly desirable to develop versatile electrode materials with extremely low overpotential for satisfying the requirements of the high-performance water-alkali electrolyzers. In this proposal, facile synthesis technologies will be developed to prepare three-dimensional bicontinuous nanoporous metal/oxide or hydroxide hybrid electrode materials that simultaneously address the mass transport of electrolyte, the surface reaction on the electrocatalysts and the electron transfer from electroactive site to current collectors. The main strategies involve developing multimodal nanoporous architecture to maximize the specific surface area and facilitate the mass transport of electrolyte, controlling multi-phase interfacial structure to minimize the internal resistance and adjusting the adsorption energy of oxides or hydroxides to optimize their catalytic activity. Therein, special attention will be paid on the relationships between geometric nanoporous structure (size and multimodal distribution of nanopores) and mass transport of electrolyte, between three-phase interfacial structure (current collector/nanoporous metal, nanoporous metal/oxide or hydroxide) and electron transfer, between the oxide or hydroxide/electrolyte interfacial properties and catalysis towards water oxidation. During the course of the study, the basic structure-activity relationships will be demonstrated for the proposals of new principles and advanced designs of nanoporous hybrid electrodes with remarkably enhanced performance. Based on the implementation of this proposal, it is expected to deepen the understanding of physical mechanisms on the interactions and coupling effects in the metal-based heterostructures, and to achieve novel and high-performance materials, promoting the development of highly efficient water-alkali electrolyzers.

发生于阳极的水氧化反应是碱水电解池水裂解制氢的关键控制步骤，决定着器件的电能/化学能转化效率。针对阳极电极系统水氧化反应催化活性低、内阻大、过电势高等瓶颈问题，本项目拟以降低水氧化反应的过电势为目标，发展脱合金与其他物理或化学方法相结合的技术，调节工艺参数可控合成高电导、高催化活性和稳定的纳米多孔金属/氧化物或氢氧化物复合电极材料。阐明复合电极材料的几何结构如纳米多孔性(孔径特征与分布)与电解液传输动力学的关系，三相界面(集流体/多孔金属、多孔金属/氧化物或氢氧化物)原子结构与电子输运性能的关系，氧化物或氢氧化物/电解液界面与水氧化反应催化活性的关系，进而揭示复合电极材料水氧化催化的本征构效关系。同时，结合工艺参数与纳米多孔金属和复合物结构演变规律，阐明多模式纳米多孔金属的形成机制和氧化物/氢氧化钠物在孔道内的生长机制。

不可再生的化石燃料消耗与排放导致严重环境污染和气候变化，影响着国民生活环境与经济的协调和可持续发展，亟待推动可再生资源如的广泛应用。围绕太阳能、风能等可再生电能驱动的电解水制氢、二氧化碳还原实现电能-化学能能量转化过程中复合电极系统中电子输运、电解液/气体分子传质动力学、表面氧化还原反应动力学等科学问题，以及大规模能量存储所需电池关键材料，本项目顺利开展研究工作。取得了如下三方面主要进展：.(1).发展了共晶模板脱合金法，结合自发相分离、水热等技术研发了满足质传动力学、电子输运和高比表面积需求的、具有多级孔结构的自支撑的纳米多孔金属/金属间化合物一体化复合电极材料，阐明了其电解水分解制氢中析氢/析氧电催化反应的构效关系。.(2).发展了脱合金原位合金化构建金属间化合物的新方法，研发了多模式纳米多孔金属/金属间化合物二氧化碳还原电催化材料，揭示了表面合金化增强二氧化碳电还原选择性的工作机制。.(3).提出了共晶合金模板导向锌和铝金属剥离/电镀抑制枝晶形成的新方法，解决了多价金属离子电池中锌和铝金属负极材料因枝晶生长所引发的效率低、寿命短等问题，研发了高稳定、长寿命的锌-和铝-基合金电极材料，发展了高性能水性锌离子电池和铝离子电池。.自本项目运行以来，在Nat. Commun.，Adv. Mater. 等学术期刊共发表文章30篇，其中影响因子大于10的20篇，申请国家发明专利5件、获得授权国家发明专利3件。以纳米多孔金属材料为主题在中国材料大会设立分会场、召开学术会议2次。项目负责人入选国家“万人计划”科技创新领军人才。培养硕士/博士毕业研究生分别3/6人。