Three-Dimensional Networked Ni-Phyllosilicate Catalyst for CO₂ Methanation: Achieving High Dispersion and Enhanced Stability at High Ni Loadings

Abstract

It is a great challenge for nickel-based catalysts to obtain high-temperature stable Ni nanoparticles with high dispersion at high loadings. To address this problem, a group of three-dimensional (3D) networked nickel phyllosilicate catalysts were prepared through the hydrothermal reaction of 3D-SBA-15 and soluble nickel salts (Ni­(NO3)2 or Ni­(CH3COO)2) and were used for the CO2 methanation reaction to produce CH4 (substitute natural gas). The flower-like nanosheets corresponding to Ni3Si2O5(OH)4 are uniformly generated on the surface of 3D-SBA-15 and become much denser with increasing hydrothermal time, with Ni contents varying in the range of 24.22–30.72 wt %. Upon 750 °C reduction of phyllosilicate materials, small-sized Ni particles (<5 nm) can highly disperse and be confined into the silica and unreduced phyllosilicate support due to the strong interaction of the nickel and complex support. In addition, a Ni/3D-SBA-15 catalyst with the high Ni content of 30 wt % was also synthesized for comparison by an incipient wetness impregnation method. For the CO2 methanation reaction, the fabricated phyllosilicate catalyst achieved a higher maximum CH4 yield of 80.4% at 400 °C and exhibited a higher long-term stability of 100 h as compared to the impregnated sample. It was noted that the phyllosilicate catalyst also exhibited high hydrothermal stability at 600 °C under 100% steam. The enhanced catalytic performance was attributed to the excellent property of nickel phyllosilicate and the special pore structure derived from 3D-SBA-15, which could significantly improve the Ni dispersion and increase CO2 adsorption and H2 uptake as well as the interaction of nickel–support.

Highly Efficient Ni-Phyllosilicate Catalyst with Surface and Interface Confinement for CO2 and CO Methanation

“…The reduction peak of NPS-180-5C shifts from 837 to 817 °C compared with that of NPS-180, indicating that the interaction between Ni­(II) species and phyllosilicate is weakened after the addition of CeO 2 species. Consistent with the reported literature studies, , the impregnated N/SR-Im shows two reduction peaks at 442 and 687 °C assigning to NiO species gathered outside the SR material and NiO species dispersed inside the mesopores, respectively. Significantly, the peak intensity of N/SR-Im at 442 °C is much stronger than that at 687 °C, which indicates that the majority NiO species exists on the outside surface of the support.…”

“…For the pore size distribution curves, the intensity of peak at around 2.3 nm decreases compared with that of the SR, and there is a new peak at around 7.8 and 12.3 nm because of the formation of granular nickel phyllosilicate on the surface of the SR material. On the other hand, it is noted that the isotherms of NPS-180, NPS-180-5C, and NPS-200 change to type IV with a hysteresis loop of type H4, and only a peak around 3.8 nm forms on the pore size distribution curves due to the formation of nanosheet-like Ni phyllosilicate . However, for the Ni-phyllosilicate samples, they still show a high surface area (≥282 m 2 g –1 ) and large pore volume (≥0.67 cm 3 g –1 ) in Table , which proves the destruction of the pores in the SR material and the formation of narrower plate-like pores over the Ni-phyllosilicate-based catalyst.…”

“…High hydrothermal stability of the catalyst is crucial for CO 2 /CO methanation because of its exothermic property and water production . In this work, the hydrothermal stability of NPS-180-5C and N/SR-Im was further investigated using 600 °C 100% steam for 6 h .…”

Enhancing the CO2 methanation activity of Ni/CeO2 via activation treatment-determined metal-support interaction

“…The CO 2 utilization, notably conversion of CO 2 into valueadded chemicals and fuels has attracted increasing interest [2] due to the prospective impact for environmental remediation and energy production [3][4][5][6]. The CO 2 hydrogenation to methane provides an effective approach for the transformation of CO 2 to fuel on a large scale with high conversion efficiency under mild conditions [7][8][9][10]. Moreover, the CO 2 to methane process shows great potential for the storage of renewable energy using a power-togas technology that converts surplus renewable electricity to methane [11,12], where H 2 production from water electrolysis and the CO 2 methanation are involved [13,14].…”

Ni/CeO2 catalysts for low‐temperature CO2 methanation: Identifying effect of support morphology and oxygen vacancy

“…The TOF value of Ni/W is even larger than that of the previous reported CO 2 methanation catalyst (Table 1). 25 Interestingly, the TOF value on Ni/W was 1.4 times higher than that on Ni/B. Moreover, the TOF value of Ni/W has advantages over the previous reported CO 2 methanation catalysts, indicating that CeO 2 as the support can effectively improve the catalytic activity at low temperature 26 .…”