Ezbiri Miriam, Allen Kyle M, Gàlvez Maria E, Michalsky Ronald, Steinfeld Aldo
Solar Technology Laboratory, Paul Scherrer Institute, 5232 Villigen-PSI (Switzerland).
Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich (Switzerland).
ChemSusChem. 2015 Jun 8;8(11):1966-71. doi: 10.1002/cssc.201500239. Epub 2015 Apr 29.
Separation and concentration of O2 from gas mixtures is central to several sustainable energy technologies, such as solar-driven synthesis of liquid hydrocarbon fuels from CO2 , H2 O, and concentrated sunlight. We introduce a rationale for designing metal oxide redox materials for oxygen separation through "thermochemical pumping" of O2 against a pO2 gradient with low-grade process heat. Electronic structure calculations show that the activity of O vacancies in metal oxides pinpoints the ideal oxygen exchange capacity of perovskites. Thermogravimetric analysis and high-temperature X-ray diffraction for SrCoO3-δ , BaCoO3-δ and BaMnO3-δ perovskites and Ag2 O and Cu2 O references confirm the predicted performance of SrCoO3-δ , which surpasses the performance of state-of-the-art Cu2 O at these conditions with an oxygen exchange capacity of 44 mmol O 2 mol SrCoO 3-δ(-1) exchanged at 12.1 μmol O 2 min(-1) g(-1) at 600-900 K. The redox trends are understood due to lattice expansion and electronic charge transfer.
从气体混合物中分离和浓缩氧气是几种可持续能源技术的核心，例如利用二氧化碳、水和聚光太阳光通过太阳能驱动合成液态烃燃料。我们提出了一种通过利用低品位过程热以逆pO₂梯度“热化学泵送”氧气来设计用于氧气分离的金属氧化物氧化还原材料的原理。电子结构计算表明，金属氧化物中氧空位的活性确定了钙钛矿理想的氧交换容量。对SrCoO₃₋δ、BaCoO₃₋δ和BaMnO₃₋δ钙钛矿以及Ag₂O和Cu₂O参比物进行的热重分析和高温X射线衍射证实了SrCoO₃₋δ的预测性能，在这些条件下，SrCoO₃₋δ的性能超过了目前最先进的Cu₂O，在600 - 900K时氧交换容量为44 mmol O₂ mol SrCoO₃₋δ⁻¹，交换速率为12.1 μmol O₂ min⁻¹ g⁻¹。由于晶格膨胀和电子电荷转移，氧化还原趋势是可以理解的。
