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Chemical looping combustion characteristics and kinetic behaviour of Sr-doped perovskite-type CaFeO3 oxygen carriers: Theoretical and experimental investigations
The Canadian Journal of Chemical Engineering ( IF 1.6 ) Pub Date : 2022-07-12 , DOI: 10.1002/cjce.24541
Nini Yuan 1 , Ziheng Han 1 , Qingjie Guo 1 , Hao Jian 1 , Jingjing Ma 1 , Hongcun Bai 1
Affiliation  

Oxygen carriers (OCs) with typical perovskite structures have attracted attention for use in chemical looping combustion (CLC) owing to their unique tunable structures and excellent performance. Thus, a further improvement in the reactivity and a deep understanding of the kinetic behaviour in CLC are highly desirable for such perovskite OCs. In this study, a series of Sr-doped perovskite-structured CaFeO3 OCs (denoted as SrxCa1−xFeO3) were synthesized. The CLC characteristics, kinetic behaviour, and doping mechanism were systematically investigated via experiments and density functional theory (DFT) calculations. The activation energies of SrxCa1−xFeO3 OCs with various Sr contents were found to be in the range of 36.6–40.1 kJ/mol and lower than that of CaFeO3 (62.7 kJ/mol), indicating that the Sr doping enhanced the reactivity of CaFeO3. Among the OCs, Sr0.4Ca0.6FeO3, which had the lowest activation energy and the fastest release of lattice oxygen, was regarded as the optimum OC. DFT calculations indicated that the reaction energy barrier of SrxCa1−xFeO3 (0.73–1.06 eV) was lower than that of CaFeO3 (2.18 eV). This suggests that Sr doping and the regulation of the reaction pathways are essential drivers for enhancing the reactivity of SrxCa1−xFeO3, which affects the release of lattice oxygen and the morphological properties of OC particles.

中文翻译:

Sr 掺杂钙钛矿型 CaFeO3 氧载体的化学链燃烧特性和动力学行为:理论和实验研究

具有典型钙钛矿结构的氧载体(OCs)由于其独特的可调结构和优异的性能而在化学链燃烧(CLC)中的应用引起了人们的关注。因此,对于此类钙钛矿 OC,非常需要进一步提高反应性和深入了解 CLC 中的动力学行为。在这项研究中,合成了一系列 Sr 掺杂钙钛矿结构的 CaFeO 3 OC(表示为 Sr x Ca 1− x FeO 3)。通过实验和密度泛函理论 (DFT) 计算系统地研究了 CLC 特性、动力学行为和掺杂机制。Sr x Ca 1− x FeO的活化能发现具有不同 Sr 含量的3 OCs 在 36.6–40.1 kJ/mol 范围内,低于 CaFeO 3 (62.7 kJ/mol),表明 Sr 掺杂增强了 CaFeO 3的反应性。在OCs中,Sr 0.4 Ca 0.6 FeO 3具有最低的活化能和最快的晶格氧释放,被认为是最佳的OC。DFT计算表明Sr x Ca 1− x FeO 3的反应能垒(0.73–1.06 eV)低于CaFeO 3(2.18 电子伏特)。这表明 Sr 掺杂和反应途径的调节是增强 Sr x Ca 1− x FeO 3反应性的重要驱动因素,这会影响晶格氧的释放和 OC 颗粒的形态特性。
更新日期:2022-07-12
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