Syngas production by $$\hbox {CO}_{2}$$ CO 2 reforming of methane on $$\hbox {LaNi}_{\mathrm{x}}\hbox {Al}_{1-\mathrm{x}}\hbox {O}_{3}$$ LaNi x Al 1 - x O 3 perovskite catalysts: influence of method of preparation

Abstract

Two series of LaNi x Al 1−x O 3 catalysts (0 ≤ x ≤ 1) were prepared by hydrothermal and sol-gel methods and characterized by X-ray diffraction (XRD), BET surface area, Temperature programmed reduction (TPR) and Fourier-transform infrared spectroscopy (FT-IR) techniques. The performance of these catalysts was studied for CO 2 reforming of methane (also called dry reforming of methane, DRM) at atmospheric pressure and in the temperature range of 600−800 • C, maintaining a space velocity of 28,800 h −1. Catalysts containing trimetallic perovskite showed higher CH 4 and CO 2 conversions than the bimetallic perovskite, due to the strong interaction of Ni with the former. Strong interaction increased the reduction temperature of the active species and reduced the sintering of metallic particles. At 800 • C, the sol-gel catalysts reached their maximum activity in terms of both CH 4 and CO 2 conversions at x = 0.3, whereas the same for hydrothermal catalysts required a Ni ratio x = 0.6. The trimetallic perovskite formation was responsible for the catalyst stability. A comparison of the best catalysts from the two series revealed that the hydrothermal catalysts exhibited a slightly better performance during the time on stream analysis. The results are interpreted in terms of changes in the physicochemical properties of the catalysts.

Steering the Methane Dry Reforming Reactivity of Ni/La2O3 Catalysts by Controlled In Situ Decomposition of Doped La2NiO4 Precursor Structures

“…Apart from the inherent economical issues concerning the use of noble metals, one particular challenge is connected to the deactivation and long-term stability of especially Ni-containing catalysts by coke formation . In the search for alternative catalyst materials, a new class of prospective compounds based on perovskite and perovskite-related structures has evolved. ,,,,, Perovskites, with the general formula ABO 3 (A usually being a lanthanide, alkaline, or earth alkaline metal ion with a valency of 2 or 3; B being a transition metal ion with a valency of 3 or 4), are often used as catalyst precursor materials that are converted into the active phase by a reductive treatment in hydrogen, triggering the partial or complete decomposition of the parent perovskite structure and the formation of a metal-oxide-system, or in-case of in situ DRM activation, of an oxide-(oxy)­carbonate system, consisting of small nm-sized metal particles attached to the oxide- or (oxy)­carbonate matrix. ,,, One particularly rewarding perovskite entity is the archetypical system LaNiO 3 , which has already shown very promising coking properties. ,,− …”

Mechanistic in situ insights into the formation, structural and catalytic aspects of the La2NiO4 intermediate phase in the dry reforming of methane over Ni-based perovskite catalysts

“…The proven importance of the La2NiO4 intermediate phase during the catalytic performance of LaNiO3 directly raises the question if this concept can be generalized to similar perovskite systems. Especially La-based single perovskite materials are well-known to exhibit considerable DRM activity, mostly, but not limited to Ni-and Co-doping on the B-site [18,30,[32][33][34][41][42][43][44][45][46][47]. In principle, each metallic dopant that can be exsolved from the B site upon either hydrogen reduction or contact to the DRM mixture and which subsequently allows for efficient methane activation, would be a prospective candidate.…”

Evaluation of Au/ZrO2 Catalysts Prepared via Postsynthesis Methods in CO2 Hydrogenation to Methanol

“…The production of carbon-based pollutants through the utilization of fossil fuels has increased enormously since the industrial revolution. Strategies to reduce CO 2 emissions in the atmosphere are essential [1][2][3][4]. In this regard, CO 2 is considered to be an abundant C1 source [5] that can be used as a raw material to produce vital value-added products, such as syngas, dimethyl ether, formic acid, methane, higher hydrocarbons, and methanol, etc.…”