纳米Ni/(La,Sr)TiO3+δ-YSZ复合阴极体系的制备与电解CO2研究

The composite cathode, Ni-YSZ, of solid oxide electrolysis cell is able to efficiently split CO2/H2O when flowing a significant concentration of reducing gas over it to produce chemical fuels, which is pretty important for the scientific research and practical application in the field of renewable energy; however, the Ni metal can be easily oxidized from Ni to NiO when performing direct high-temperature electrolysis, which leads to the significant degradation of solid oxide electrolysis cell performances. Redox-stable (La,Sr)TiO3+δ-YSZ composite cathode is able to perform the direct electrolysis; however, the insufficient catalytic activity still hinders the cathode kinetic process. This proposal aims to develop a Nano-sized Ni/(La,Sr)TiO3+δ-YSZ composite cathode through the reversible exsolution of Ni metal particles and evaluate the electrode process and electrochemical process of the electrolysis of CO2. The Ni particle size and distribution as well as the cathode microstructure will be tailored to enhance the electro-catalytic performance of composite cathode. The Ni/(La,Sr)TiO3+δ interface, which is created by anchoring the Ni particles on the surface of (La,Sr)TiO3+δ ceramic, will be studied to understand its effects on the improvements of high-temperature and long-term stability of the composite catohde. The improvements of cathode cycling performance by using the advantage of reversible dissolution of Ni particles into (La,Sr)TiO3+δ substrate will be also investigated. This proposal aims to develop a high-performance and redox-stable composite cathode which is able to perform direct electrolysis based on the synergetic effect of the catalytic activity of Nano-sized Ni particles and the redox stability of (La,Sr)TiO3+δ ceramic. A general method will be developed to prepare composite cathode composed of Nano-sized metal particles and ceramic substrate, which is expected to contribute to the research and development of composite cathode with sufficient electro-catalytic activity and redox stability.

固体氧化物电解池Ni-YSZ阴极经还原气氛保护可高效电解CO2/H2O，在再生能源方面具有重要的学术研究价值和应用前景，但直接电解会氧化金属Ni导致电解池性能衰竭。氧化还原稳定的(La,Sr)TiO3+δ-YSZ陶瓷阴极可直接高温电解，但催化活性不足仍制约阴极动力学过程。本项目拟通过金属原位可逆析出制备纳米Ni/(La,Sr)TiO3+δ-YSZ复合阴极，研究高温电解CO2的电极动力学过程和电化学能量转换过程。通过调控纳米Ni颗粒尺寸与分布,优化阴极微结构提高电催化性能；利用界面锚合改善电极的高温和长期稳定性；探讨纳米Ni高温氧化可逆溶解对阴极热循环性能的增强作用。基于纳米Ni的催化活性和(La,Sr)TiO3+δ陶瓷的氧化还原稳定性的耦合机制，获得可直接高温电解且性能优良的复合阴极体系，发展纳米金属/陶瓷复合电极体系的一般制备方法，为固体氧化物电解池阴极材料的发展提供有价值的参考。

固体氧化物电解池Ni-YSZ阴极经还原气氛保护可高效电解CO2/H2O，在再生能源方面具有重要的学术研究价值和应用前景，但直接电解会氧化金属Ni导致电解池性能衰竭。氧化还原稳定的(La,Sr)TiO3+δ-YSZ陶瓷阴极可直接高温电解，但催化活性不足仍制约阴极动力学过程。本项目先通过调控钙钛矿型(La,Sr)TiO3+δ 的成分比例筛选综合电性能优良的陶瓷电极材料，然后将金属元素如Fe、Ni和Cu等催化活性元素在(La,Sr)TiO3+δ陶瓷材料的制备过程中掺杂进入晶格合成(La,Sr)1-xTi1-xMxO3+δ(M=Fe, Ni和Cu)材料体系，通过还原将纳米金属原位析出锚在(La,Sr)TiO3+δ基体表面，可控构筑纳米金属/(La,Sr)TiO3+δ-YSZ复合阴极体系。我们深入研究并阐明了金属/氧化物界面对复合阴极的高温和长期稳定性的增强机制；同时研究并揭示复合阴极微结构促进高温电解电极动力学过程的规律；并基于纳米金属颗粒高温氧化原位可逆溶解进入陶瓷基体生成单相陶瓷，获得了热循环性能和氧化还原稳定性。本项目在材料制备方面，阐明纳米金属原位可逆溶解和析出的动力学过程和条件，揭示制备其他纳米金属/陶瓷复合材料体系的一般规律，为探索纳米/陶瓷复合电极体系的催化性能与应用提供有价值的参考。本项目在电化学能量转换过程方面，基于该新型纳米金属/陶瓷复合体系评价了水蒸气高温电解和二氧化碳电解的电化学能量转换过程，实现了直接高温电解水蒸气和二氧化碳制备燃料，并揭示了复合电极体系催化动力学过程。