Unbounding the Future: Designing NiAl-Based Catalysts for Dry Reforming of Methane

Dry reforming of methane (DRM), the catalytic conversion of CH4 and CO2 into syngas (H2+CO), is an important process closely correlated to the environment and chemical industry. NiAl-based catalysts have been reported to exhibit excellent activity, low cost, and environmental friendliness. At the same time, the rapid deactivation caused by carbon deposition, Ni sintering, and phase transformation exerts great challenges for its large-scale applications. This review summarizes the recent advances in NiAl-based catalysts for DRM, particularly focusing on the strategies to construct efficient and stable NiAl-based catalysts. Firstly, the thermodynamics and elementary steps of DRM, including the activation of reactants and coke formation and elimination, are summarized. The roles of Al2O3 and its mixed oxides as the support, and the influences of the promoters employed in NiAl-based catalysts over the DRM performance, are then illustrated. Finally, the design of anti-coking and anti-sintering NiAl-based catalysts for DRM is suggested as feasible and promising by tailoring the structure and states of Ni and the modification of Al-based supports including small Ni size, high Ni dispersion, proper basicity, strong metal-support interaction (SMSI), active oxygen species as well as high phase stability.

Solution combustion synthesis of Ni/La2O3 for dry reforming of methane: tuning the basicity via alkali and alkaline earth metal oxide promoters

The production of syngas via dry reforming of methane (DRM) has drawn tremendous research interest, ascribed to its remarkable economic and environmental impacts. Herein, we report the synthesis of K, Na, Cs, Li, and Mg-promoted Ni/La₂O₃ using solution combustion synthesis (SCS). The properties of the catalysts were determined by N₂ physisorption experiments, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), and H₂-TPR (temperature programmed reduction). In addition, their catalytic performance towards DRM was evaluated at 700 °C. The results demonstrated that all catalysts exhibited porous structures with high specific surface area, in particular, Mg-promoted Ni/La₂O₃ (Mg–Ni–La₂O₃) which depicted the highest surface area and highest pore volume (54.2 m² g⁻¹, 0.36 cm³ g⁻¹). Furthermore, Mg–Ni–La₂O₃ exhibited outstanding catalytic performance in terms of activity and chemical stability compared to its counterparts. For instance, at a gas hourly space velocity (GHSV) of 30 000 mL g⁻¹ h⁻¹, it afforded 83.2% methane conversion and 90.8% CO₂ conversion at 700 °C with no detectable carbon deposition over an operating period of 100 h. The superb DRM catalytic performance of Mg–Ni–La₂O₃ was attributed to the high specific surface area/porosity, strong metal-support interaction (MSI), and enhanced basicity, in particular the strong basic sites compared to other promoted catalysts. These factors remarkably enhance the catalytic performance and foster resistance to coke deposition.

Alkali and alkaline earth metal oxides-promoted Ni/La₂O₃ catalysts synthesized by solution combustion synthesis revealed enhanced catalytic performance towards dry reforming of methane.

Nb2O5 as a radical modulator during oxidative dehydrogenation and as a Lewis acid promoter in CO2 assisted dehydrogenation of octane over confined 2D engineered NiO–Nb2O5–Al2O3

Ordered mesoporous 2D NiO–Nb₂O₅–Al₂O₃ nano-composites were used for CO₂ assisted dehydrogenation of n-octane; and the close proximity of Ni and Nb₂O₅ in the optimised catalyst promoted CO₂ dissociation and substantially prolonged alkane activation.

One-pot synthesis of a highly mesoporous Ni/MgAl2O4 spinel catalyst for efficient steam methane reforming: influence of inert annealing

The inert annealing step during the synthesis of the Ni/MgAl₂O₄ catalyst induces positive changes in the catalyst substructure. The obtained catalyst displayed high catalytic activity towards steam methane reforming with low carbon deposition.

Facile one-step preparation of ordered mesoporous Ni–M–Al (M = K, Mg, Y, and Ce) oxide catalysts for methane dry reforming

Excellent DRM performances of a Ni–Y–Al oxide catalyst is related to the comprehensively advantageous textural properties, such as high Ni dispersion, large surface area, and small Ni nanoparticles inlaid in the honeycomb-like mesoporous skeleton.

Effects of preparation method and Sm2O3 promoter on CO methanation by a mesoporous NiO–Sm2O3/Al2O3 catalyst

Well-dispersed Ni and Sm₂O₃ nanoparticles embedded in an ordered mesoporous Al₂O₃ material simultaneously exhibit high catalytic activity and stability for the CO methanation reaction.

Ultrasound assisted co-precipitation synthesis and catalytic performance of mesoporous nanocrystalline NiO-Al2O3 powders

Mesoporous nanocrystalline NiO-Al₂O₃ powders with high surface area were synthesized via ultrasound assisted co-precipitation method and the potential of the selected samples as catalyst was investigated in dry reforming reaction for preparation of synthesis gas. The prepared samples were characterized by N₂ adsorption (BET), X-ray diffraction (XRD), Temperature programmed reduction and oxidation (TPR, TPO) and scanning electron microscopy (SEM) techniques. The effects of pH, power of ultrasound irradiation, aging time and calcination temperature on the textural properties of the catalysts were studied. The sample prepared under specified conditions (pH10, 70W, without aging time and calcined at 600°C) exhibited the highest surface area (249.7m²g^-1). This catalyst was calcined at different temperature and employed in dry reforming of methane and the catalytic results were compared with those obtained over the catalysts prepared by impregnation and co-precipitation methods. The results showed that the catalyst prepared by ultrasound assisted co-precipitation method exhibited higher activity and stability with lower degree of carbon formation compared to catalysts prepared by co-precipitation and impregnation methods.

Highly stable mesoporous NiO–Y2O3–Al2O3 catalysts for CO2 reforming of methane: effect of Ni embedding and Y2O3 promotion

A series of mesoporous NiO–Y₂O₃–Al₂O₃ composite oxides with different yttrium contents were synthesized by either a one-pot evaporation-induced self-assembly (EISA) method or impregnation for carbon dioxide reforming of methane (CRM).

Factors affecting the long-term stability of mesoporous nickel-based catalysts in combined steam and dry reforming of methane

Direct “one-pot” synthesis is highly efficient to obtain performing mesoporous Ni–Al₂O₃catalysts able to resist deactivation by sintering and coke deposition during CH₄reforming by CO₂and H₂O to produce “metgas”.

Structured catalysts for dry reforming of methane

This review highlights the progress in designing oxide catalysts with well defined structures for dry reforming of methane.

Mesoporous materials for clean energy technologies

Alternative energy technologies are greatly hindered by significant limitations in materials science. From low activity to poor stability, and from mineral scarcity to high cost, the current materials are not able to cope with the significant challenges of clean energy technologies. However, recent advances in the preparation of nanomaterials, porous solids, and nanostructured solids are providing hope in the race for a better, cleaner energy production. The present contribution critically reviews the development and role of mesoporosity in a wide range of technologies, as this provides for critical improvements in accessibility, the dispersion of the active phase and a higher surface area. Relevant examples of the development of mesoporosity by a wide range of techniques are provided, including the preparation of hierarchical structures with pore systems in different scale ranges. Mesoporosity plays a significant role in catalysis, especially in the most challenging processes where bulky molecules, like those obtained from biomass or highly unreactive species, such as CO2 should be transformed into most valuable products. Furthermore, mesoporous materials also play a significant role as electrodes in fuel and solar cells and in thermoelectric devices, technologies which are benefiting from improved accessibility and a better dispersion of materials with controlled porosity.

One-step synthesis of ordered mesoporous CoAl2O4 spinel-based metal oxides for CO2 reforming of CH4

Ordered mesoporous CoAl₂O₄ spinel-based metal oxides were facilely synthesized and utilized as the catalysts for CRM reactions.

In situ controllable assembly of layered-double-hydroxide-based nickel nanocatalysts for carbon dioxide reforming of methane

The dual confinement effects from alumina and LDH precursors produced a new nanoplates-on-pore structure with a uniform distribution and smaller size of Ni nanoparticles (NPs) for the LDOs/γ-Al₂O₃, while enhanced catalytic performance and better resistance to sintering and coking.

Effect of pore geometries on the catalytic properties of NiO–Al2O3 catalysts in CO2 reforming of methane

Mesoporous NiO–Al₂O₃ catalysts were prepared by an evaporation-induced self-assembly (EISA) method, during which the amount of HNO₃ added in the precursor solution was varied.

One-pot synthesis of ordered mesoporous transition metal–zirconium oxophosphate composites with excellent textural and catalytic properties

A series of ordered M–X–ZrPO materials were successfully synthesized via a facile and general one-pot evaporation-induced self-assembly (EISA) strategy.

Synthesis of dendrimer-templated Pt nanoparticles immobilized on mesoporous alumina for p-nitrophenol reduction

Dendrimer-templated mesoporous alumina-supported Pt nanocatalysts were prepared and used to catalyze reduction reaction after calcination at different temperatures in nitrogen.

Significant roles of mesostructure and basic modifier for ordered mesoporous Ni/CaO–Al2O3 catalyst towards CO2 reforming of CH4

The significant roles of mesostructure and basic modifier in improving the catalytic performance of dry reforming were investigated.