CO₂ Activation over Nanoshaped CeO₂ Decorated with Nickel for Low-Temperature Methane Dry Reforming

Abstract

Dry reforming of methane (DRM) is a promising way to convert methane and carbon dioxide into H 2 and CO (syngas). CeO 2 nanorods, nanocubes, and nanospheres were decorated with 1−4 wt % Ni. The materials were structurally characterized using TEM and in situ XANES/EXAFS. The CO 2 activation was analyzed by DFT and temperature-programmed techniques combined with MS-DRIFTS. Synthesized CeO 2 morphologies expose {111} and {100} terminating facets, varying the strength of the CO 2 interaction and redox properties, which influence the CO 2 activation. Temperature-programmed CO 2 DRIFTS analysis revealed that under hydrogen-lean conditions mono-and bidentate carbonates are hydrogenated to formate intermediates, which decompose to H 2 O and CO. In excess hydrogen, methane is the preferred reaction product. The CeO 2 cubes favor the formation of a polydentate carbonate species, which is an inert spectator during DRM at 500 °C. Polydentate covers a considerable fraction of ceria's surface, resulting in less-abundant surface sites for CO 2 dissociation.

Efficient Calcium Looping-Integrated Methane Dry Reforming by Dual Functional Aerosol Ca–Ni–Ce Nanoparticle Clusters

“…Tian et al reported that Ca–Ni interfaces in the CaO–Ni material favored CH 4 dissociation and achieved 65% of CO 2 conversion at 800 °C; Hu et al incorporated thermally stable CeO 2 to CaO–Ni materials, resulting in 90% of CO 2 conversion at a relatively low temperature (650 °C); Kim et al used MgO–Al 2 O 3 as a support material to prepare CaO–Ni@MgO–Al 2 O 3 , where 99.9% of CO 2 conversion was achieved at 720 °C . Overall, the incorporation of catalyst promoters (e.g., ceria) has been shown to improve the activity and stability of the Ni-based catalyst. ,,,, The Ca–Ce and Ca–Ni–Ce interfaces provide alternative catalytic pathways to enhance carbonation and DRM, respectively, instead of using CaO and Ni alone. , …”

“…9 Overall, the incorporation of catalyst promoters (e.g., ceria) has been shown to improve the activity and stability of the Ni-based catalyst. 4,13,19,24,28 The Ca−Ce and Ca−Ni−Ce interfaces provide alternative catalytic pathways to enhance carbonation and DRM, respectively, instead of using CaO and Ni alone. 1,9 However, the present DFM prepared by the conventional approach (e.g., using a sol−gel-based coprecipitation method) possessed several drawbacks that limited the effectiveness of CO 2 conversion.…”

Calculation of Entropy for a Two-Dimensional (2D) Ideal Gas with a Statistical Thermodynamic Method

“…For different molecules, there may also be a corresponding correlation in the medium temperature range, and its slope value is different from that of Campbell–Sellers correlation. In the application fields of linear correlation, such as heterogeneous catalysis, the temperature usually exceeds 400 K which means it is in the medium temperature range. ,− In this case, it may be more appropriate to use this linear correlation in the medium temperature range.…”

Mechanism study on gliding arc (GA) plasma reforming: Unraveling the decisive role of CH4/CO2 ratio in the dry reforming reaction

“…[12] Furthermore, catalysts have also been used to combine with plasma, aiming to improve conversion, selectivity, and energy efficiency. [3,[13][14][15] Meanwhile, the various experimental conditions, such as discharge power, [16] gas flow rate, [5] pressure, [17] and CH 4 /CO 2 molar ratio [8] (for simplification, CH 4 /CO 2 is used to stand for CH 4 /CO 2 molar ratio in the following sections), have been extensively investigated in above plasma types. The previous efforts have made significant improvements in raising the reactant conversion and energy efficiency of plasma reforming to be close to that in industrial thermo-catalysis.…”