A Short Review on Ni‐Catalyzed Methanation of CO₂: Reaction Mechanism, Catalyst Deactivation, Dynamic Operation

Abstract

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Today, the use of renewable energies and recycling of climate-changing gases are increasingly important. In this context, coupling of methanation with small, decentralized CO 2 sources such as biogas plants provides one possibility. However, fluctuating availability of renewables for hydrogen production in combination with small storage volumes result in an enhanced demand for dynamic process operation. This leads to new research challenges with respect to the required catalysts and the overall process design. To draw reliable conclusions about the catalytic performance under dynamic process operation, the mechanism of the methanation reaction as well as typical deactivation procedures of the catalyst applied under steady-state conditions have to be reviewed thoroughly.

Methane synthesis from CO2 and H2O using a phosphate-based electrochemical cell at 210–270 °C with oxide-supported Ru catalysts

“…A large number of studies have been published on CO 2 methanation (Sabatier reaction) with H 2 . 43–48 The present three catalysts are very typical examples, and there is significant room for improvement. In this study, a 1.5 mm layer comprising 400–800 mg of catalyst was used.…”

Recent Advances in Catalysis for Methanation of CO2 from Biogas

“…However, if the reaction proceeds via CO as an intermediate (so-called carbide mechanism), reaction networks in which formate or carboxyl intermediates are formed have also been observed [32]. The carbide mechanism proceeds from CO 2 via CO either to C (carbide) + O (not shown here) or to OCH 2 and OCH 3 as intermediates, which are hydrogenated to CH 4 (Figure 2) [31,33,34]. The formate mechanism proceeds from CO 2 via CO, HCOO − , and C to CH 4 [31].…”

“…To overcome these activation barriers and to reach high CO2 conversions Catalysts 2022, 12, x FOR PEER REVIEW 5 of 36 also been observed [32]. The carbide mechanism proceeds from CO2 via CO either to C (carbide) + O (not shown here) or to OCH2 and OCH3 as intermediates, which are hydrogenated to CH4 (Figure 2) [31,33,34]. The formate mechanism proceeds from CO2 via CO, HCOO -, and C to CH4 [31].…”

“…The toxicity of sulfur-containing molecules increases with the number of free electron pairs available for bonding and with lower shielding of the S atom, as well as with increasing electronegativity [63]. These factors make H 2 S more toxic than oxidized sulfur-containing molecules such as SO 2 [33]. It has been observed that catalyst deactivation by H 2 S proceeds in three prominent phases, which are visible, for example, in CO 2 conversion as depicted in Figure 4: 1.…”

Effect of Fe and La on the Performance of NiMgAl HT-Derived Catalysts in the Methanation of CO2 and Biogas

“…The methanation or Sabatier reaction is a feasible solution to valorize CO 2 − or, directly, biogas. , Among all the active phases reported in the literature for the hydrogenation of CO 2 into CH 4 , Ni is the most investigated one, since it combines high CH 4 productivity and low cost; , it is suitable for both CO 2 and direct biogas methanation. − The activity of Ni-based catalysts is related to the Ni loading, particle size, and type of support . The support plays an important role in stabilizing small metallic particles and activating the CO 2 ; therefore, basic sites are preferred .…”