CH₄ as the paramount ingredient of natural gas plays an eminent role in C1 chemistry. CH₄ catalytically converted to syngas is a significant route to transmute methane into high value-added chemicals. Moreover, the CO/CO₂ methanation reaction is one of the potent technologies for CO₂ valorization and the coal-derived natural gas production process. Due to the high thermal stability and high extent of dispersion of metallic particles, two-dimensional mixed metal oxides through calcined layered double hydroxides (LDHs) precursors are considered as the suitable supports or catalysts for both the reaction of methanation and methane reforming. The LDHs displayed compositional flexibility, small crystal sizes, high surface area and excellent basic properties. In this paper, we review previous works of LDHs applied in the reaction of both methanation and methane reforming, focus on the LDH-derived catalysts, which exhibit better catalytic performance and thermal stability than conventional catalysts prepared by impregnation method and also discuss the anti-coke ability and anti-sintering ability of LDH-derived catalysts. We believe that LDH-derived catalysts are promising materials in the heterogeneous catalytic field and provide new insight for the design of advance LDH-derived catalysts worthy of future research.

As a methanation tool, two-dimensional (2D) carrier-loaded Ni has attracted the attention of many researchers. We successfully prepared 2D MgAl layered double oxides (LDO) carriers via flash nanoprecipitation (FNP). Compared to the LDO samples prepared by conventional co-precipitation (CP), the 2D MgAl-LDO (FNP) has more oxygen vacancies and more exposed active sites. The Ni/MgAl-LDO (FNP) catalyst demonstrates a CO conversion of 97%, a CH₄ selectivity of 79.8%, a turnover frequency of 0.141 s⁻¹, and a CH₄ yield of 77.4% at 350 °C. The weight hourly space velocity was 20,000 mL∙g⁻¹∙h⁻¹ with a synthesis gas flow rate of 65 mL∙min⁻¹, and a pressure of 1 atm. A control experiment used the CP method to prepare Ni/MgAl-LDO. This material exhibits a CO conversion of 81.1%, a CH₄ selectively of 75.1%, a TOF of 0.118 s⁻¹, and a CH₄ yield of 61% at 450 °C. We think that this FNP method can be used for the preparation of more 2D LDO catalysts.

Expanded multilayered vermiculite (VMT) was successfully used as catalyst support and Ni/VMT synthesized by microwave irradiation assisted synthesis (MIAS) exhibited excellent performance in our previous work. We also developed a two-dimensional porous SiO2 nanomesh (2D VMT-SiO2) by mixed-acid etching of VMT. Compared with three-dimensional (3D) MCM-41, 2D VMT-SiO2 as a catalyst support provided a superior position for implantation of NiO species and the as-obtained catalyst exhibited excellent performance. In this paper, we successfully synthesized a layered double hydroxide (LDH) using the spent liquor after mixed-acid etching of VMT, which mainly contained Mg2+ and Al3+. The as-calcined layered double oxide (LDO) was used as a catalyst support for CO methanation. Compared with Ni/MgAl-LDO, Ni/VMT-LDO had smaller active component particles; therefore, in this study, it exhibited excellent catalytic performance over the whole temperature range of 250–500 °C. Ni/VMT-LDO achieved the best activity with 87.88% CO conversion, 89.97% CH4 selectivity, and 12.47 × 10−2·s−1 turn over frequency (TOF) at 400 °C under a gas hourly space velocity of 20,000 mL/g/h. This study demonstrated that VMT-LDO as a catalyst support provided an efficient way to develop high-performance catalysts for synthetic natural gas (SNG) from syngas.

Identification of active site is critical for developing advanced heterogeneous catalysis. Here, a nickel/silica (Ni/SiO₂) catalyst was prepared through an ammonia-evaporation method for CO methanation. The as-obtained Ni/SiO₂ catalyst shows a CO conversion of 96.74% and a methane selectivity of 93.58% at 623 K with a weight hourly space velocity of 25,000 mL·g⁻¹·h⁻¹. After 150 h of continuous testing, the CO conversion still retains 96%, which indicates a high catalyst stability and long life. An in situ vacuum transmission infrared spectrum demonstrates that the main active sites locate at the interface between the metal Ni and the SiO₂ at a wave number at 2060 cm⁻¹ for the first time. The interesting discovery of the active site may offer a new insight for design and synthesis of methanation catalysts.