This study addresses an enhanced CO₂ conversion of mesoporous La_0.8Sr_0.2FeO₃ (LSF) perovskite synthesized using a nanocasting method in reverse water gas shift chemical looping (RWGS-CL) process. The effects of controlled template removal from the nanocast LSF on its textural property and resulting redox reactivity were thoroughly investigated. LSF was first impregnated on SBA-15 (a mesoporous silica template), which was removed by NaOH etching to monitor the residual Si content. Specific surface area, total pore volume, and metal dispersion of the nanocast LSF were dramatically enhanced as the residual Si content decreased, but Si contents of < 5 wt% caused the mesoporous structure to collapse. Temperature-programmed experiments revealed that both the reactivity and capacity of reducible oxygen were maximized by optimizing residual Si content at 10 wt%. XPS analyses showed that the atomic ratio of surface oxygen to lattice oxygen, a key indicator of CO productivity, was also maximized at a Si content of 10 wt%. The mesoporous LSF with this Si content achieved the highest average CO yield of 2.80 mmol/g for RWGS-CL at 600 °C, which was 5.9 fold-higher than that achieved by bulk LSF.

本研究致力于提高介孔 La _0.8 Sr _0.2 FeO _{3 的}CO ₂转化率(LSF) 钙钛矿在反向水煤气变换化学循环 (RWGS-CL) 工艺中使用纳米铸造方法合成。彻底研究了从纳米铸造 LSF 中受控模板去除对其结构特性和由此产生的氧化还原反应性的影响。LSF 首先浸渍在 SBA-15（一种介孔二氧化硅模板）上，然后通过 NaOH 蚀刻去除以监测残留的 Si 含量。随着残留 Si 含量的降低，纳米铸造 LSF 的比表面积、总孔容和金属分散显着增加，但 < 5 wt% 的 Si 含量会导致介孔结构崩溃。程序升温实验表明，通过将残余 Si 含量优化为 10 wt%，可最大限度地提高可还原氧的反应性和容量。XPS 分析表明，表面氧与晶格氧的原子比（CO 生产率的关键指标）在 Si 含量为 10 wt% 时也最大化。具有这种 Si 含量的介孔 LSF 在 600°C 下为 RWGS-CL 实现了最高的平均 CO 产率 2.80 mmol/g，比本体 LSF 实现的 CO 产率高 5.9 倍。