Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane

Abstract

Dry reforming of methane (DRM) is one of the more promising methods for syngas (synthetic gas) production and co-utilization of methane and carbon dioxide, which are the main greenhouse gases. Magnesium is commonly applied in a Ni-based catalyst in DRM to improve catalyst performance and inhibit carbon deposition. The aim of this review is to gain better insight into recent developments on the use of Mg as a support or promoter for DRM catalysts. Its high basicity and high thermal stability make Mg suitable for introduction into the highly endothermic reaction of DRM. The introduction of Mg as a support or promoter for Ni-based catalysts allows for good metal dispersion on the catalyst surface, which consequently facilitates high catalytic activity and low catalyst deactivation. The mechanism of DRM and carbon formation and reduction are reviewed. This work further explores how different constraints, such as the synthesis method, metal loading, pretreatment, and operating conditions, influence the dry reforming reactions and product yields. In this review, different strategies for enhancing catalytic activity and the effect of metal dispersion on Mg-containing oxide catalysts are highlighted.

Effects of Zr Doping into Ceria for the Dry Reforming of Methane over Ni/CeZrO2 Catalysts: In Situ Studies with XRD, XAFS, and AP-XPS

“…Only H 2 O, H 2 , and CO were detected via gas chromatography and a residual gas analyzer (RGA) (RGA spectra are provided in Figure S3) as the products, and the reaction rates of H 2 O, H 2 , and CO were 67, 710, and 960 μmol/g cat /s, respectively. The reverse water gas shift reaction (RWGS: H 2 + CO 2 ↔ H 2 O + CO) is one of the undesirable side reactions accompanying DRM, which consumes a product (H 2 ) and transforms it to H 2 O, thus reducing H 2 selectivity and the H 2 /CO stoichiometric ratio. , From Figure c, we can see that H 2 selectivity rises with increasing temperature, and, at different temperatures, it remains higher on Ni/CeZrO 2 than on Ni/CeO 2 . This suggests a suppression of the RWGS reaction at higher temperatures with the assistance of Zr in the support. − Overall, Ni/CeZrO 2 exhibits better catalytic performance than Ni/CeO 2 , with a higher CH 4 and CO 2 conversion, higher reaction rate, and a higher selectivity for H 2 .…”

Supported Ni Single-Atom Catalysts: Synthesis, Structure, and Applications in Thermocatalytic Reactions

“…The mechanism of this reaction has been thoroughly studied [109,110]. The reaction begins with the adsorption of a methane molecule on the catalytically active center (2), followed by its activation (3), which is the rate-determining stage of the reaction [111,112]:…”

“…The second way to modify the catalyst by introducing additional basic centers into it is to add a metal and/or its oxide to the support. The creation of such centers will enhance the chemisorption of CO 2 on them [109]. As for the Zr and Ce atoms mentioned above, their addition to oxygen-containing supports also increased the mobility of oxygen ions on the surface, making Ni catalysts more stable [117].…”

Synergistic Syngas Production: Needleless Electrospinning Synthesis of Co/CeO2–La2O3 Catalyst for Efficient Dry Reforming of Methane

“…Over the years, the abundance of greenhouse gases, namely methane and carbon dioxide, directly linked to environmental and ecological issues, has increased [1,2]. Recent studies have focused on harnessing catalyst-driven dry reforming of methane (DRM) as a viable approach for converting these gases to a valuable feedstock for energy generation purposes [3,4].…”