Impact of magnesium substitution on the structural stability and catalytic performance of LaNiO₃ perovskites for methane dry reforming
Parisa Ebrahimi, Anand Kumar, Mohammed J. Al‐Marri
Abstract
Mg-doped LaNiO 3 perovskite nanoparticles , denoted as LaNi x Mg 1-x O 3 (0 ≤x ≤ 1), were prepared via the solution combustion technique and evaluated for dry reforming of methane. The results suggest that at 750 °C, a nickel content 0.57 achieved optimal conversion rates of 86% for CO 2 and 77% for CH 4 , as determined by the Design of Experiment (DOE) analysis. These findings were subsequently experimentally confirmed through the synthesis of LaNi 0.5 Mg 0.5 O 3 . The TPR analysis revealed that partially substituting Ni with Mg raised the reduction peak temperatures, indicating a more stable perovskite structure that is harder to reduce compared to LaNiO 3 . Notably, all catalysts, except LaMgO 3 , demonstrated high activity for generating syngas in the DRM reaction, the replacement of Ni with Mg did not significantly enhance the catalytic efficiency of LaNi 0.5 Mg 0.5 O 3 ; however, the samples showed enhanced stability with the inclusion of Mg. The XRD patterns of the synthesized LaNi x Mg 1-x O 3 solids indicated that with higher concentrations of Mg, the development of the perovskite phase was hindered; instead, spinel (La 2 NiO 4 ) and oxide phases (MgO and NiO) appeared on the surface of the sample.