Engineering a Nickel–Oxygen Vacancy Interface for Enhanced Dry Reforming of Methane: A Promoted Effect of CeO₂ Introduction into Ni/MgO

Abstract

Nickel, the most commonly used active metal for the dry reforming of methane (DRM), often encounters the challenge of severe deactivation due to sintering and carbon deposition. In this study, we introduce cerium into Ni/MgO, a traditional catalyst for DRM, to improve its activity and stability, resulting in an enhanced Ni/MgCeO x catalyst. With the optimized doping amount of cerium (Ce/Mg = 0.12), the catalyst demonstrates a conversion rate 65% for CH4, 75% for CO2, and a H2/CO ratio of 0.76, while the Ni/MgO catalyst only achieves a conversion rate of 57% for CH4, 65% for CO2, and a H2/CO ratio of 0.68. Furthermore, the introduction of cerium significantly improves the stability of the catalyst. These improved activity and stability can be attributed to the easy reducibility of NiO x species, small Ni particle size, and abundant oxygen vacancies resulting from the doping of cerium. The affinity between CeO2 and NiO x inhibits the formation of the NiO-MgO solid solution, which contributes to the enhanced performance.

Solvent-Free Ball-Milling-Derived Ni-CeO2/SiO2 Catalysts for CO2 Methanation

“…The lines of Si, O, Ni, and Ce elements are detected from all spectra (Figure a). The Ni 2p 3/2 XPS spectra (Figure b) can be fitted into four peaks representing metallic Ni 0 (binding energy (BE)) of (∼852.7 eV), Ni 2+ (I) (∼854.2 eV), Ni 2+ (II) (∼856.0 eV), and the Ni shakeup satellite (∼861.2 eV). − The presence of Ni 2+ as NiO species on the catalyst surface is attributed to the surface reoxidation upon exposure to atmospheric conditions during sample handling prior to XPS analysis . With increasing CeO 2 content, the BE of Ni 0 shifts from 852.8 to 852.6 eV, indicating an increased electron cloud density of Ni.…”

Research Progress on Stability Control on Ni-Based Catalysts for Methane Dry Reforming

“…Similarly, among a series of Ni-Ce x Zr 1−x O 2 and Ni-Ce x Ti 1−x O 2 catalysts with varying Ce/Zr and Ce/Ti molar ratios (x = 0, 0.25, 0.5, 0.75, and 1), Ni-Ce 0.5 Zr 0.5 O 2 and Ni-Ce 0.5 Ti 0.5 O 2 delivered the highest apparent activity and stability for combined steam and CO 2 reforming of CH 4 in each series due to small Ni particles, strong metal-support interaction, and high oxygen vacancy concentration [71]. Ding et al [72] also find that doping the optimized amount of cerium (Ce/Mg = 0.12) into Ni/MgO catalyst can improve activity and stability, which are attributed to the easy reducibility of NiO x species, small Ni particle size, and abundant oxygen vacancies resulting from the doping of cerium.…”

Recent Advances in Coke Management for Dry Reforming of Methane over Ni-Based Catalysts

“…The doping of Eu in CeO2 increased the oxygen mobility and storage capacity, maintaining a balanced rate between the carbon formation and carbon oxidation, and resulting in a reduced accumulation of coke (Figure 4) [81]. CeO2 doping can also attenuate the affinity between MgO and NiOx through interactions with NiO, inhibit the formation of a NiO-MgO solid solution, and promote the reduction of Ni species [82]. La2O3, as a DRM support, can enhance the adsorption and activation of CO2 [83].…”