One-Pot Synthesis of Ordered Mesoporous NiO–CaO–Al₂O₃Composite Oxides for Catalyzing CO₂Reforming of CH₄

Abstract

Ordered mesoporous tricompound NiO−CaO−Al 2 O 3 composite oxides with various Ca content were first designed and facilely synthesized via a one-pot, evaporation-induced, self-assembly (EISA) strategy. The obtained mesoporous materials with advantageous textural properties and superior thermal stabilities were investigated as the catalysts for the carbon dioxide reforming of methane reaction. These mesoporous catalysts entirely showed high catalytic activities as well as long catalytic stabilities toward this reaction. The improved catalytic activities were suggested to be closely associated with the advantageous structural properties, such as large specific surface areas; big pore volumes; and uniform pore sizes, which could provide sufficient "accessible" active centers for the gaseous reactants. In addition, the "confinement effect" of the mesoporous matrixes contributed to stabilizing the Ni active sites during the processes of reduction and reaction, accounting for the long lifetime stabilities of these mesoporous catalysts. The modification of Ca played dual roles in promoting the catalytic activities and suppressing the carbon deposition by enhancing the chemisorption of the CO 2 . Generally, the ordered mesoporous NiO−CaO−Al 2 O 3 composite oxides could be considered as promising catalysts for the carbon dioxide reforming of methane reaction.

Catalytic Abatement of Nitrous Oxide Coupled with Ethane Oxydehydrogenation over Mesoporous Cr/Al2O3 Catalyst

“…Figure 3 shows the nitrogen adsorption and desorption isotherms as well as the pore size distribution as an inset. As shown in Figure 3, the sample calcined at 700 °C gave type IV curve with H1-shaped hysteresis loop, which was the typical feature of ordered mesoporous materials with uniform mesopores [22,23] among the framework of the Cr/Al2O3 material. The deduction of H1-shaped hysteresis loops in Figure 3 further confirmed the cylindrical pores along [1 1 0] in TEM analysis.…”

“…Figure 3 shows the nitrogen adsorption and desorption isotherms as well as the pore size distribution as an inset. As shown in Figure 3, the sample calcined at 700 • C gave type IV curve with H1-shaped hysteresis loop, which was the typical feature of ordered mesoporous materials with uniform mesopores [22,23] In addition, the pore size distribution exhibited in the inset of Figure 3 was extremely narrow, and the position of the peak was located in 5.2 nm. The large surface area and narrow pore size distribution of this ordered mesoporous alumina-based material, in combination with the advantageous thermal stability, enhance its potential applications in catalysis.…”

Ordered mesoporous “one-pot” synthesized Ni-Mg(Ca)-Al2O3 as effective and remarkably stable catalysts for combined steam and dry reforming of methane (CSDRM)

“…Comparable stability effects were recently claimed in the case of "one-pot" synthesized oxide-based catalysts tested in DRM [43,45,51,52,61] or in SRM [46], but such types of materials were never considered yet in the combined CSDRM reaction that involves much more drastic conditions (especially steam and high temperatures). Moreover, the present method introducing the active phase (Ni) and the structuring agent (P123 Pluronic triblock copolymer) in a same synthesis batch was, to our knowledge, never considered regarding nickel-alumina based mesoporous catalysts.…”

“…As far as we know, such approach combining (i) structuration of the porous alumina support and (ii) active phase -and supplementary element -insertion within the catalyst matrix by "one-pot" synthesis was not yet considered for the CSDRM reaction (Table 1). Low cost and widely available Mg 2+ and Ca 2+ containing salts were chosen as additives based on their potentiality to yield basic properties (in their oxide form) and on their known positive impact on CSDRM (Table 1) and DRM [50][51][52]. For the sake of completion, the influences of the Ni content (5-10 wt% range) and of the nature and amount of the identified carbon species on the activity level and long-term stability were also considered.…”

Assembly of ordered mesoporous alumina-supported nickel nanoparticles with high temperature stability for CO methanation

“…Here, ordered mesoporous alumina (OMA)-supported nickel oxide was obtained using a modified one-pot method. Upon reduction, the Ni NPs were highly dispersed and stabilized in the pore channels of the OMA (Scheme 1b) [12][13][14]. We applied a Ni-OMA catalyst in a CO methanation reaction, and tested the stability of the catalysts in long-term high-temperature stability tests.…”