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The nanorod morphology of the CeO2 support has been recognized as more beneficial than other morphologies for catalytic activity in the dry reforming of methane. Ni/nanorod-CeO2 catalysts with different Ni contents were prepared by one-pot hydrothermal synthesis. Samples were characterized by X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), H2-temperature-programmed desorption (H2-TPD), field emission scanning electron microscopy/energy dispersive spectroscopy (FE-SEM/EDS), Brunauer–Emmet–Teller (BET) and Barrett–Joyner–Halenda (BHJ) analysis. The effect of Ni content on the size and the intrinsic strain of ceria was analyzed by the Size–Strain plot and Williamson–Hall plot of XRD data. The average Ni particle size and Ni dispersion were determined by H2-TPD. XRD and H2-TPR analysis revealed a strong Ni–support interaction that limited nickel sintering. The activity for the dry reforming of methane was tested with the stoichiometric mixture CO2:CH4:N2:He = 20:20:20:140, gas hourly space velocity (GHSV) = 300 L g−1 h−1, and temperatures in the range of 545–800 °C. The turnover frequency (TOF) value increased linearly with the average Ni particle size in the range of 5.5–33 nm, suggesting the structure sensitivity of the reaction. Samples with Ni loading of 4–12 wt.% showed high H2/CO selectivity and stability over time on stream, whereas the sample with a Ni loading of 2 wt.% was less selective and underwent rapid deactivation. Only a small amount of nanotubular carbon was observed by FE-SEM after the time-on-stream experiment. Deactivation of the low-Ni-content sample is ascribed to the easier oxidation of the small Ni particles.

Carbon dioxide collected from outdoor atmosphere or produced in aerospace cabin, may be recycled to produce methane and water by methanation reaction (Sabatier reaction). This reaction needs a heterogeneous catalyst to decrease the reaction temperature and increase the selectivity. A proper catalyst for in-situ CO 2 recycling into methane requires: i) high CO 2 conversion with high CH 4 selectivity at low operating temperature, ii) high stability towards degradation, being required that catalyst remains highly active during the entire production process. This paper presents a preliminary study of a catalyst based on Ni supported on cerium oxide, prepared by one-pot hydrothermal method, leading to a nanorod morphology with high and uniform nickel dispersion. Morphology and chemical properties of the material were characterized by BET, H 2 -TPR, XRD and FE-SEM/EDS. The catalyst was tested in a flow system at atmospheric pressure, using reagents with stoichiometric ratio (CO 2 :H 2 =1:4) or enriched in hydrogen. The Ni/r-CeO 2 catalyst showed high stability over time on stream, in oxidizing condition and after switch off-switch on test.

Carbon dioxide is the principal greenhouse gas produced by fossil fuels combustion. The CO2 methanation (Sabatier reaction) CO2 + 4H2 → CH4 + 2H2O combines the valorisation of CO2 with the storage of surplus energy by renewable sources (solar, wind), in the power to gas process (PtG). The present work uses ceria nanorods as support for metallic nickel. The Ce1-xNixO2-δ catalysts with different nickel content (x = 0.05; 0.10; 0.20; 0.30) were prepared by hydrothermal synthesis. Catalysts have been characterized by XRD, BET, H2-TPR, H2-TPD, FESEM, with the aim to verify the structure–sensitivity of the methanation on nickel. The catalytic activity and selectivity were studied using different CO2:H2 molar ratios, under atmospheric pressure, in the temperature range 200–500°C and gas hourly space velocity (GHSV) 300.000 cm3 h-1 g-1. The stability tests were performed at 400°C and GHSV 300.000 cm3 h-1 g-1 under fluctuating reaction conditions.

Ni-based oxides are widely investigated as catalysts for CO2 methanation due to their high activity, high selectivity and low cost. The catalytic performances of Ni-based catalysts depend on support properties that strongly influence the dispersion of the catalytic active phase and the Ni&ndash, support interaction. Although the CO2 methanation is widely studied, the structure sensitivity of methanation on nickel is not completely assessed. Ni/CeO2 nanorods with different nickel/ceria molar ratios (0.05, 0.10, 0.20, 0.30) were prepared by one-pot hydrothermal synthesis. The effect of nickel content and metal particle size on catalytic activity and selectivity for CO2 methanation were studied using CO2:H2 = 1:4 stoichiometric ratio at high space velocity (300 L g&minus, 1 h&minus, 1). Sample structure and morphology were studied by X-ray diffraction (XRD), Brunauer&ndash, Emmet&ndash, Teller (BET) analysis, field-emission scanning electron microscopy/energy-dispersive spectroscopy (FE-SEM/EDS), H2-temperature programmed reduction (TPR), H2-temperature-programmed desorption (TPD). Both the CO production and the turnover frequency appear depending on nickel particle size, suggesting a structure sensitivity of the CO2 methanation on nickel supported on ceria.

In in-situ resource utilization and in atmosphere revitalization processes, CO 2 may be recycled to produce methane and water by Sabatier reaction. The traditional Ni/γ-Al 2 O 3 catalyst for Sabatier reaction was modified by addition of rare earth oxides La 2 O 3 and/or CeO 2 in order to improve activity, selectivity and stability. Preliminary results showed that La addition improved activity and CH 4 selectivity against CO more than Ce addition. Catalytic activity was tested using stoichiometric flow (CO 2 :H 2 = 1:4) without dilution.

Although some recent developments in nanotechnology made the prospects of a direct mechanical manipulation of micro- or nano-objects quite realistic, there are still several concerns and difficulties that affect such an endeavor. This is probably due to the large base of knowledge that is necessary to approach the problem of handling a nano-object by means of a nano- or micro-device. Therefore, any progress in this field is possible only by means of an integrated and interdisciplinary approach, which takes into account different aspects of the phenomenon. During the actual pioneering phase, there is a certain convenience in handling nano-objects that: (a) have peculiar known characteristics, (b) are easily recognizable, and (c) are interesting to the scientific community. This paper presents the interdisciplinary activities that were necessary to set up an experiment where specifically synthesized SiO2 particles came in contact with the tips of specifically-designed and -fabricated nanomanipulators. SiO2 mesoporous nanoparticles (KCC-1), having a peculiar dendritic structure, have been selected as a suitable nano-object because of the possibility to easily modulate their morphology. The expected contact force has been also calculated by means of Finite Element Analysis (FEA) electro-mechanical simulations.