太阳能驱动的化学链技术能够将丰富的太阳能资源转化为易于利用和储存的形式，可直接获得供地质封存的CO2，近零能耗原位分离产生的高纯氢、CO和合成气，其关键在于氧载体的循环与氧传递。针对目前氧载体高载氧量和高循环稳定性难以兼顾的问题，本项目提出利用六铝酸盐优异的高温稳定性和活性组分可镶嵌性，将大量Fe离子（Fe wt%=60%）镶嵌进入六铝酸盐晶格框架内制备高铁容量六铝酸盐作为氧载体，并揭示其在高温氧化还原过程中的载氧和稳定机制；针对氧载体在高温氧化还原条件下表征困难的问题，本项目提出以Fe为探针，借助57Fe穆斯堡尔谱等多种表征手段及理论计算，阐明高铁容量六铝酸盐在周期性氧化还原循环过程中的微观结构变化特征及其与甲烷转化和CO2/H2O分解化学链反应性能的内在关联机制。此项目能够为氧载体高载氧量高循环稳定性难以兼顾应用瓶颈的突破奠定基础，为开发新型高效长寿命氧载体提供理论基础与研制方向。

Chemical looping via a solar-driven thermochemical process opens a novel pathway to convert the abundant solar energy into readily utilizable and storable forms, which can produce a sequestration-ready stream of CO2, pure hydrogen, CO and syngas without extra energy consumption. The success of chemical looping highly depends on the circulation and oxygen-carrying of oxygen carrier. It is difficult for oxygen carrier to have both high oxygen donation ability and high cyclic stability. Combined with the excellent high-temperature stability and the substitution of Al3+ by active metal ions, we proposed to incorporate a large amount of Fe ions (Fe wt%=60%) into the structure of hexaaluminate and use the prepared high-iron capacity hexaaluminate as oxygen carrier. We will uncover the oxygen-carrying and stabilization mechanism of high-iron capacity hexaluminate oxygen carrier in the high-temperature redox process. It is difficult to characterize the microstructure of oxygen carrier during reduction and re-oxidation process under high temperature. By employing Fe as probe and a series of characterization technologies and theoretical calculation, we will establish the relationship between the microstructure of high-iron capacity hexaaluminate oxygen carrier during the successive redox cyclic process and the chemical looping reaction performance for methane conversion and CO2/H2O splitting. The project can establish foundation to develop oxygen carrier with both high oxygen donation ability and high cyclic stability, and provide theoretical and technical principles for the rational design of oxygen carriers with high efficiency and long life-time.