Thermochemical conversion of carbon dioxide by reverse water-gas shift chemical looping using supported perovskite oxides
Thermochemical conversion of carbon dioxide by reverse water-gas shift chemical looping using supported perovskite oxides
复制标题
DOI：
10.1016/j.cattod.2018.06.002
复制
发表时间：
2019-02-15
期刊：
影响因子：
5.3
通讯作者：
Kuhn, John N.
中科院分区：
文献类型：
--
作者：
Hare, Bryan J.;Maiti, Debtanu;Kuhn, John N.
钙钛矿型氧化物显示出明显的热化学太阳能驱动的CO2转化潜力。这些材料表现出确切的特性（e。例如，在一个实施例中，结构耐久性和高的氧氧化还原能力和交换动力学）。在这项研究中，La0.75Sr0.25FeO3（LSF）钙钛矿氧化物与各种载体相结合，包括流行的氧化还原材料CeO 2和ZrO 2沿着更丰富的替代品，如Al 2 O3，SiO2和TiO 2，在工业规模的潜在应用。在SiO2上负载25%质量的LSF导致在600 ℃下还原后相对于未负载的钙钛矿的CO产率最大增加150%。这是通过SEM/TEM成像和来自XRD图案的Scherrer分析的微晶尺寸证实的显著降低的钙钛矿氧化物粒度的结果。由于固态反应，次要的第二相观察到在LSF：支持界面时，使用SiO2或TiO 2。氧空位的形成只发生在钙钛矿氧化物相，建议由低温实验和密度泛函理论计算相一致。阐明了每种金属氧化物载体对抑制或增强CO2转化的作用。通过利用SiO2作为载体，使用钙钛矿基复合材料的逆水煤气变换化学链过程得到显著改善。
Perovskite-type oxides show clear potential for thermochemical solar-driven CO2 conversion. These materials exhibit the exact characteristics (e. g., structural endurance and high oxygen redox capacity and exchange kinetics) required by the low temperature reverse water-gas shift chemical looping process. In this study, the La0.75Sr0.25FeO3 (LSF) perovskite oxide was combined with various supports, including popular redox materials CeO2 and ZrO2 along with more abundant alternatives such as Al2O3, SiO2, and TiO2, for potential application at industrial scale. Supporting LSF on SiO2 by 25% mass resulted in the largest increase of 150% in CO yields relative to unsupported perovskite after reduction at 600 degrees C. This is a result of significantly reduced perovskite oxide particle size confirmed by SEM/TEM imaging and crystallite size from Scherrer analyses of XRD patterns. Due to solid-state reactions, minor secondary phases were observed at the LSF: support interface when using SiO2 or TiO2. Oxygen vacancy formation occurred only on the perovskite oxide phase, as suggested by low temperature experiments and consistent with density functional theory calculations. The role of each metal oxide support towards suppressing or enhancing the CO2 conversion is elucidated. Through utilization of SiO2 as support, the reverse water-gas shift chemical looping process using perovskite-based composites was significantly improved.