Syngas production via auto-thermal methane reforming using modified perovskite catalysts: Performance evaluation of La1−xGdxNiO3-δ perovskite oxides

Abstract

A series of Gadolinium (Gd) substituted LaNiO3 nano catalyst specified as La1−xGdxNiO3-δ (x = 0, 0.3, 0.5, 0.7, 0.9 and 1) were synthesized by the modified citrate sol-gel method and applied in auto-thermal reforming of methane (ATR). The results of characterization techniques indicated all samples have a highly homogeneous and crystalline structure with particle sizes in the range of nano meters. X-Ray diffraction (XRD) patterns confirmed a pure crystallinity perovskite phase without the presence of any other crystalline phases for the samples with low Gd content (x = 0, 0.1). The formation of spinel (La2NiO4) and oxide (NiO, Gd2O3) phases could be increased by degree of substitution (x). Brunauer–Emmett–Teller (BET) results showed that the presence of Gd in the catalyst structure increases the specific surface area of the samples. Temperature programmed reduction (TPR) analysis showed difficult reduction pattern by enhancing the degree of substitution (x). Partial substitution of La by Gd was investigated in ATR process under reaction temperature range of 600 to 800 °C. All catalysts represented a high catalytic activity and stability toward syngas production via ATR process at 800 °C while at lower temperatures, the La1−xGdxNiO3-δ (x = 0, 0.1, 0.9 and 1) showed the highest activity.