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<p>A series of samarium-doped Nickel (Ni) catalysts supported on three-dimentional (3D) mesoporous silica (KIT-6) were synthesized, characterized, and evaluated for the dry reforming of methane (DRM) in this study. Ni-based catalysts with 5 wt% Ni and varying samarium (Sm) loadings (0–1.5 wt%) were synthesized via the wet impregnation method and characterized by X-ray diffraction (XRD), nitrogen (N<sub>2</sub>) physisorption, hydrogen temperature-programmed reduction (H<sub>2</sub>-TPR), carbon dioxide temperature-programmed desorption (CO<sub>2</sub>-TPD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Raman spectroscopy. The catalytic efficiency was evaluated in a fixed-bed tubular reactor at 700&#xa0;°C using a feed composition of methane (CH<sub>4</sub>): CO<sub>2</sub>: N<sub>2</sub> = 3:3:1 with a gas hourly space velocity (GHSV) of 42&#xa0;L g<sup>− 1</sup> h<sup>− 1</sup>. The promotional effect of Sm on the concentration of active sites, catalyst reducibility, and basicity was strong. The most effective catalyst was 0.75 wt% Sm-promoted 5Ni-KIT-6 (5Ni+0.75Sm-KIT-6), which acquired the smallest NiO crystallite size, a higher degree of reducibility, the highest surface area, and the maximum density of basic sites. This catalyst achieved a maximum CH<sub>4</sub> conversion of 60% at 700 ℃ and 90% at 850 ℃ and exhibited excellent stability over 400&#xa0;min. The low activation energies (Ea<b>)</b> (45.7 for CH<sub>4</sub> and 42.9&#xa0;kJ mol<sup>–1</sup> for CO<sub>2</sub>) indicate high catalytic efficiency with minimal diffusion limitations, while the kinetic results followed Arrhenius predictions well. Raman studies of the spent catalysts confirmed that Sm promotion prevented the formation of graphitic carbon and thus the deactivation of active sites. The present study confirmed the superior performance of Sm-promoted Ni/KIT-6 in producing stable, high-yielding syngas via DRM, suggesting a green procedure for the valorization of greenhouse gases.</p> Graphical Abstract <p></p>

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Tailoring the 3D Mesoporous Structure of Ni/KIT-6 Catalysts Via Samarium Promotion for Enhanced Stability and Carbon Resistance in Dry Reforming of Methane

  • 期刊论文

  • 发表日期：

    2026年7月27日

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  • Tahani Saad Algarni,
  • Abdulaziz A. M. Abahussain,
  • Ahmed A. Ibrahim,
  • Salwa B. Alreshaidan,
  • Khaled M. Banabdwin,
  • Rehab M. Ali,
  • Nadavala Siva Kumar,
  • Ahmed S. Al-Fatesh

摘要

A series of samarium-doped Nickel (Ni) catalysts supported on three-dimentional (3D) mesoporous silica (KIT-6) were synthesized, characterized, and evaluated for the dry reforming of methane (DRM) in this study. Ni-based catalysts with 5 wt% Ni and varying samarium (Sm) loadings (0–1.5 wt%) were synthesized via the wet impregnation method and characterized by X-ray diffraction (XRD), nitrogen (N2) physisorption, hydrogen temperature-programmed reduction (H2-TPR), carbon dioxide temperature-programmed desorption (CO2-TPD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Raman spectroscopy. The catalytic efficiency was evaluated in a fixed-bed tubular reactor at 700 °C using a feed composition of methane (CH4): CO2: N2 = 3:3:1 with a gas hourly space velocity (GHSV) of 42 L g− 1 h− 1. The promotional effect of Sm on the concentration of active sites, catalyst reducibility, and basicity was strong. The most effective catalyst was 0.75 wt% Sm-promoted 5Ni-KIT-6 (5Ni+0.75Sm-KIT-6), which acquired the smallest NiO crystallite size, a higher degree of reducibility, the highest surface area, and the maximum density of basic sites. This catalyst achieved a maximum CH4 conversion of 60% at 700 ℃ and 90% at 850 ℃ and exhibited excellent stability over 400 min. The low activation energies (Ea) (45.7 for CH4 and 42.9 kJ mol–1 for CO2) indicate high catalytic efficiency with minimal diffusion limitations, while the kinetic results followed Arrhenius predictions well. Raman studies of the spent catalysts confirmed that Sm promotion prevented the formation of graphitic carbon and thus the deactivation of active sites. The present study confirmed the superior performance of Sm-promoted Ni/KIT-6 in producing stable, high-yielding syngas via DRM, suggesting a green procedure for the valorization of greenhouse gases.

Graphical Abstract