Lanthanum calcium manganite perovskite coated on porous ceria for enhanced solar thermochemical fuel production

Abstract

This study explores the enhanced efficiency of solar-driven redox reactions using ceria foams coated with Ca-doped lanthanum manganite (LCM) perovskite, focusing on sustainable fuel production. The effects of substrate pore density (10, 30 ppi) and coating thickness (3 and 6 perovskite layers) were investigated. The LCM perovskite was synthesized and uniformly coated onto porous ceria substrates, as confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dual-scale porous structure of ceria enhanced the coating’s effectiveness and reactivity, with coating thicknesses ranging from 75-140 μm (three layers) to 100–400 μm (six layers). Thermogravimetric analysis (TGA) showed superior reduction extents for LCM-coated ceria samples, with O₂ production up to 131 µmol/g, compared to 55 µmol/g for pure ceria. This led to a 20–40 % increase in total fuel production, with CO yields up to 141 µmol/g versus 98 µmol/g for pure ceria. Performance stability for CO₂ and H₂O splitting was confirmed through fifteen consecutive cycles in a high-temperature solar reactor. Solar thermochemical cycling tests showed that LCM-coated ceria foams produced up to 244 µmol/g CO, with a peak CO production rate of 6.22 mL·min^-1·g^-1, during reduction at 1450 °C and oxidation under pure CO₂ below 900 °C. However, pure ceria exhibited faster oxidation kinetics. This research underscores the importance of material design and optimization in improving solar thermochemical processes for large-scale solar fuel production.