Impact of magnesium substitution on the structural stability and catalytic performance of LaNiO_₃ perovskites for methane dry reforming

Mg-doped LaNiO₃ perovskite nanoparticles, denoted as LaNi_xMg_1-xO₃ (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 CO₂ and 77% for CH₄, as determined by the Design of Experiment (DOE) analysis. These findings were subsequently experimentally confirmed through the synthesis of LaNi_0.5Mg_0.5O₃. 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 LaNiO₃. Notably, all catalysts, except LaMgO₃, 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_0.5Mg_0.5O₃; however, the samples showed enhanced stability with the inclusion of Mg. The XRD patterns of the synthesized LaNi_xMg_1-xO₃ solids indicated that with higher concentrations of Mg, the development of the perovskite phase was hindered; instead, spinel (La₂NiO₄) and oxide phases (MgO and NiO) appeared on the surface of the sample.

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Published in: Gas Science and Engineering
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.jgsce.2024.205530