Progress in reaction mechanisms and catalyst development of ceria-based catalysts for low-temperature CO₂methanation

Abstract

We present a detailed review on the mechanistic understanding and catalyst development of CeO2-based CO2 methanation catalysts. Current challenges for deeper investigations and future perspectives are presented as well.

Ionic Nickel Embedded in Ceria with High Specific CO2 Methanation Activity

“…In addition, partially reduced CeO x is inactive towards CO 2 hydrogenation (Figure S14), indicating that Ce 3+ ‐O V pairs are not sufficient for methanation reaction. This observation put forward ionic Ni‐Ce 3+ pairs as efficient reaction sites, contrary to the commonly accepted notion that metallic Ni and Ce 3+ are the active sites for CO 2 hydrogenation [11, 16, 18, 21–23, 42, 44] . The rather unexpected reactivity scheme is interpreted on the grounds of first principles calculations combined with ambient pressure XPS experiments.…”

“…Reducible oxides, such as TiO 2 and CeO 2 have been widely used as supports for CO 2 methanation and in almost all cases were found to enhance the catalytic performance as compared to more inert supports such as Al 2 O 3 or SiO 2 [8, 9] . Among the many reducible supports, CeO 2 has attracted strong interest in the field of CO 2 valorisation because Ce 4+ can be easily reduced to Ce 3+ and create oxygen vacancy (O V ) sites [10–12] . The combination of the above mentioned characteristics established CeO 2 ‐supported Ni catalysts as one of the most studied and promising candidates for the CO 2 methanation reaction [13, 14] …”

“…[8,9] Among the many reducible supports, CeO 2 has attracted strong interest in the field of CO 2 valorisation because Ce 4 + can be easily reduced to Ce 3 + and create oxygen vacancy (O V ) sites. [10][11][12] The combination of the above mentioned characteristics established CeO 2 -supported Ni catalysts as one of the most studied and promising candidates for the CO 2 methanation reaction. [13,14] Although the factors controlling the performance of Ni/ CeO 2 methanation catalysts are far from being completely understood, there is consensus that the Ni particle size, [9,[15][16][17] the interaction at the Ni-CeO 2 interphase [16,18,19] and the reducibility of ceria [20,21] are the most critical features of the catalyst.…”

Double-Edged Sword Effect of Classical Strong Metal–Support Interaction in Catalysts for CO2 Hydrogenation to CO, Methane, and Methanol

“…The Sabatier reaction, also known as CO 2 methanation (CO 2 + 4H 2 → CH 4 + 2H 2 O, Δ H 298 K = −165.0 kJ mol –1 ) is a highly exothermic process that is favored at low temperatures (<400 °C). − The reaction is considered to be one of the promising technologies for power-to-gas because it can be conducted at moderate temperatures and ambient pressure, and the produced CH 4 can be injected into the existing natural gas grid for transportation or locally used. , Ni and Ru supported on reducible oxides are the most active catalysts for CO 2 methanation; important examples of these are discussed in this section. Ni-based materials are the most extensively studied catalysts because of their relatively low price. − …”

Reversal of methanation-oriented to RWGS-oriented Ni/SiO2 catalysts by the exsolution of Ni2+ confined in silicalite-1

“…7 In contrast, Ni-based catalysts are commonly used in CO 2 methanation due to their high binding strength of *CO. 8 The Ni(111) plane of Ni nanoparticles is suggested to be the primary facet for the *CO conversion pathway. 9 Sometimes, the interface between Ni and its supports (e.g., ZnO, 10 MgO, 11 and CeO 2 12 ) induces metal-support interactions (MSIs) to facilitate methanation. Vogt et al 13 have revealed the structure-activity correlation of Ni nanoclusters (1-7 nm) in CO 2 methanation.…”