Why Ni/CeO2 is more active than Ni/SiO2 for CO2 methanation? Identifying effect of Ni particle size and oxygen vacancy

S-Doped NiII-Triazolate Derived Ni–S–C Catalyst for Electrochemical CO2 Reduction to CO

“…As shown in Figure , the pyrolyzed product is mainly composed of Ni 3 S 2 , evidenced by the identification of 2θ at 21.8°, 31.1°, 37.8°, 38.3°, 44.4°, 49.7°, 50.1°, 54.6°, and 55.2°, which corresponds to the (101), (110), (003), (021), (202), (113), (211), (104), (122) planes, respectively, of Ni 3 S 2 (PDF#30-0863) . The existence of Ni (PDF#04-0850) was supported by the recognition of diffraction peaks at 2θ = 44.5°, 51.7°, and 76.3°, corresponding to (111), (200), and (220) planes, respectively . No obvious NiO signal was observed.…”

Ionic Nickel Embedded in Ceria with High Specific CO2 Methanation Activity

“…[5] 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][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.…”

“…A plethora of supporting materials has been studied for this reaction, extending from conventional zeolites to more elaborated configurations such as core/shell structures or metal‐organic frameworks (MOFs) [5] . 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] .…”

“…[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. Despite the ongoing debate on the optimal Ni particle size, [8,9,[15][16][17] there is general belief that metallic Ni is essential for CO 2 methanation, while ionic Ni deteriorates the catalytic reaction. [22] In sharp contrast to this picture, in the present work, using well defined Ni-doped ceria nanoparticles as catalyst, we show that metallic nickel is not indispensable for the CO 2 methanation reaction.…”

Effect of catalyst properties on selectivity in CO2 methanation with coupling pathway of RWGS and CO methanation

“…19 La 2 O 3 can also react with CO 2 to generate La 2 O 2 CO 3 which helps eliminate carbon deposition. 20 In addition, the existence of oxygen vacancies is beneficial for both CO 2 activation 9,16,21,22 and the intermediate CO further dissociating to produce CH 4 . 23,24 CeO 2 was a common additive that was widely used for CO 2 conversion owing to its good reducibility and high oxygen storage capacity.…”