The effects of partial substitution of Ni by Zn in LaNiO3 perovskite catalyst for methane dry reforming

Abstract

A series of LaNi1−xZnxO3 (x=0.2, 0.4, 0.6, 0.8 and 1.0) perovskite-type oxides were synthesized via sol–gel related method by using propionic acid as solvent. The reaction was performed under continuous flow of feed stream which included CO2, CH4 and helium as diluting agent, under atmospheric pressure. The prepared catalysts were characterized by X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The results showed that the conversion rates of CO2 and CH4 increased as Ni was partially substituted by Zn. Considering the mentioned rates, among these catalysts, LaNi0.8Zn0.2O3 was the most effective catalyst. TPR results showed that partial substitution of Ni by Zn increased the temperatures of reduction peaks, leading to the more stable perovskite structure compared to LaNiO3 structure. It indicates that Zn stabilizes the perovskite structure. Also, TGA results showed that LaNi0.8Zn0.2O3 was more resistant to coke formation in comparison with LaNiO3 during 75h time on stream stability test.