Dry reforming of methane by La_0.5Sr_0.5NiO₃ perovskite oxides: influence of preparation method on performance and structural features of the catalysts

Abstract

BACKGROUND: The dry reforming of methane (DRM) process has received considerable attention for the production of syngas owing to its great environmental and economic benefits. LaNiO 3 and La 0.5 Sr 0.5 NiO 3 nanoparticles were synthesized with the coprecipitation procedure using distilled and magnetic distilled water, and examined as catalysts in DRM. RESULTS: The structure and morphology of the prepared nanoparticles were characterized by X-ray diffraction, the Brunauer-Emmett-Teller method, scanning and transmission electron microscopy, and temperature-programmed reduction, desorption and hydrogenation techniques. The experimental results proved that the treated La 0.5 Ni 0.5 SrO 3 catalyst had better initial performance in DRM in comparison with the LaNiO 3 catalyst, due to its greater surface basicity. The orientation for deposition of carbon over the surface of the consumed catalysts was as follows: La 0.5 Sr 0.5 NiO 3 treated > La 0.5 Sr 0.5 NiO 3 non-treated > LaNiO 3 nontreated > LaNiO 3 treated. CONCLUSION: Among the synthesized catalysts, the treated La 0.5 Sr 0.5 NiO 3 sample exhibited higher initial DRM activity, due to its greater surface basicity. Also, the higher surface basicity of the strontium-substituted catalyst led to an increase in CO 2 desorption and coke deposition according to the Boudouard reaction.

Highly dispersed Ni-based catalysts derived from the LaNiO3 perovskite for dry methane reforming: promotional effect of the Ni0–Ni2+ dipole inlaid on the support

“…12,15,16 The second peak (peak β) is related to the reduction of NiO to the metallic Ni 0 state, which is consistent with the result of Yusuf et al 22,26,32,33 Besides, the third peak (peak γ) corresponds to the reduction of Ni 2+ to the metallic Ni 0 state in the LaNiO 3 perovskite (Table 1). 17,27,34,35 It can be seen that there are α and γ peaks in the LNO-CA and LNO-CAE samples prepared by the sol–gel method with different chelating agents. Moreover, the area ratio of α / γ is about 1 : 2 because the LNO-CA and LNO-CAE samples are only made of the LaNiO 3 perovskite, which is consistent with the transformation of the structure of the LaNiO 3 perovskite during the reduction process.…”

The influence of Ni stability, redox, and lattice oxygen capacity on catalytic hydrogen production via methane dry reforming in innovative metal oxide systems

“…In addition, this structure allows for numerous substitutions at the B site (Ni) by the cations Mg, Al, Mn, Fe, Co, Fe, Cu, Zn, Ce, Rh, and Ru, as well as at the A site (La) by the following cations Ca, Ba, Sr, Ce, and Pr 7,12,14–40 . Substitution of A site ions with those of a lower oxidation state can affect the stability in a reducing environment and the movement of oxygen ion vacancies.…”