La<sub>0.6</sub>Sr<sub>0.4</sub>Cr<sub>0.8</sub>Co<sub>0.2</sub>O<sub>3</sub>Perovskite Decorated with Exsolved Co Nanoparticles for Stable CO<sub>2</sub>Splitting and Syngas Production
Alfonso J. Carrillo, Kun Joong Kim, Zachary D. Hood, Alexander H. Bork, Jennifer L. M. Rupp
Abstract
Exsolution is an auspicious processing route for the fabrication of catalytically active nanoparticles that are anchored into the oxide backbone, presenting inherent long-term stability benefits. Here, we show that the exsolution method can be effectively applied to create metallic nanoparticles that improve the syngas production performance under chemical-looping methane reforming coupled with CO2 splitting. The La0.6Sr0.4Cr0.8Co0.2O3 perovskite surface was functionalized with exsolving metallic Co nanoparticles of around 30 nm which exhibited remarkable microstructural stability and uniform dispersion after 28 cycles at 900 °C. The highly dispersed exsolved nanoparticles activated methane partial oxidation, increasing the syngas selectivity and fuel production rates, namely, 44 mLH2 min–1 g–1, which was a twofold improvement over the bare perovskite. In addition, surface modification via exsolution enhanced the CO2-splitting rate, ca. 100 mLCO min–1 g–1, faster than that of state-of-the-art ceria, ca. 70 mLCO min–1 g–1. The results illustrate that exsolved nanoparticles play a critical role in improving the fuel production performance while presenting high durability, denoting its relevance for high-temperature thermocatalytic processes for syngas production.