Carbon Dioxide Reforming of Methane over Nickel-Supported Zeolites: A Screening Study

Abstract

As the utilization of zeolites has become more frequent in the dry reforming of methane (DRM) reaction, more systematic studies are required to evaluate properly the influence of zeolites’ composition and framework type on the performance. Therefore, in this work, a step-by-step study was performed with the aim of analyzing the effects of Ni loading (5, 10 or 15 wt.% over USY(3) zeolite), Si/Al ratio (3, 15 or 38 on USY zeolites with 15 wt.% Ni) and framework type (USY, BEA, ZSM-5 or MOR for 15 wt.% Ni and Si/Al ratios of ≈40) on catalysts’ properties and performances. Increasing Ni loadings enhanced CH4 and CO2 conversions even though the catalysts’ stability was decreasing over the time. The variation of the Si/Al ratio on USY and the use of different zeolites had also a remarkable impact on the catalytic performance. For instance, at 500–600 °C reaction temperatures, the catalysts with higher basicity and reducibility exhibited the best results. However, when the temperature was further increased, catalysts presenting stronger metal–support interactions (nickel nanoparticles located in mesoporous cavities) displayed the highest conversions and stability over time. In brief, the use of 15 wt.% Ni and a USY zeolite, with both micro- and mesopores and high surface area, led to the best performances, mainly attributed to a favorable number of Ni0 active sites and the establishment of stronger metal–support interactions (due to nanoparticles confinement inside the mesopores).

Interplay Between Ni and Brønsted and Lewis Acid Sites in the Hydrodesulfurization of Dibenzothiophene

“…Following synthesis, we performed nitrogen adsorption‐desorption isotherms and XRD analysis to verify our assumption (see Figures S19 and S20 in the SI). We opted for these techniques as they serve as indirect methods for assessing the dispersion of a metallic phase over a support [79–86] . In summary, the analysis of the additional tests confirmed that Ni impregnated by the SEA method does not alter the textural and structural properties of the support, unlike the wet impregnation method (see to Appendix K in the SI).…”

Smart Designs of Zeolite-Based Catalysts for Dry Reforming of Methane: A Review

“…Also, Rh particle agglomeration was seen for 4 wt % Rh/H-Beta, while the coke formed was only 0.1 and 0.2 wt % for 0.5 and 1 wt % Rh/H-Beta, reflecting that a high loading led to metal aggregation because of the weaker interaction with zeolite support, while a low loading facilitated carbon gasification on the better-dispersed metal particles (Table 2). 155,156 Similarly in Co/zeolite Y, although 10% Co/zeolite Y exhibited a higher initial activity than 5% Co/zeolite Y owing to more active sites, a conversion drop was shown in the stability test, which was a result of the Co sintering and coke deposition in 10% Co/zeolite Y. 121 However, a small metal loading may hinder reactant activation.…”

Recent Developments on CO2 Hydrogenation Performance over Structured Zeolites: A Review on Properties, Synthesis, and Characterization

“…Their research delivers a clear message on how the Si/Al ratio in zeolite membranes affects the separation performance; therefore, this approach may be used for the enhancement of CO2 hydrogenation processes. Bacariza and coworkers [30] looked into the influence of Ni loading and Si/Al ratio on the behavior of framework zeolites during the dry reforming of methane (DRM). It was revealed that the ratio of Si/Al influenced tremendously the catalytic activity, which showed outstanding results of low alkalinity and higher reducibility at lower temperatures.…”