Abstract
This study explores the catalytic performance of solution combustion-synthesized doped defective fluorite catalysts, La(2-)(x)Sr(x)Ce(2-)(y)Ni(y)O(7), for the dry reforming of methane. A comprehensive structural analysis, supported by theoretical calculations, revealed that the adopted synthetic methodology enabled Ni doping beyond a critical concentration, leading to its occupation of the interstitial lattice sites. The optimally doped Ni-containing defective fluorite oxide La(1.9)Sr(0.1)Ce(1.7)Ni(0.3)O(7) exhibited superior catalytic activity with more than 70% conversion of CO(2) and CH(4) with an H(2)/CO ratio of 0.7 for a 50-h reaction at 700 °C. The prolonged reforming reaction also resulted in minimal coke deposition (11 μg(c) g(cat)(-1) h(-1)), primarily due to the oxidative dissociation pathway of methane, as revealed through mechanistic analysis. Detailed surface studies highlighted the crucial role of metal-support interactions, wherein facile electron transfer from Ni to Ce during the reaction contributed significantly to the enhanced catalytic performance. Thus, this study establishes a strategic framework for designing and developing defect-engineered oxide catalysts, paving the way for advanced materials in dry methane reforming.