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A series of ordered mesoporous Ni–Fe–Al ternary oxide composites were prepared via a one-pot evaporation-induced self-assembly (EISA) method and applied in a CO methanation reaction to produce synthetic natural gas. The results showed that the ordered mesoporous Ni–Fe–Al catalyst with proper amount of Fe species (10N1FOMA) had better both CO conversion and CH4 selectivity than the impregnation-derived 10N1FA catalyst with unordered mesopores and identical component, owing to the higher Ni dispersion and larger H2 uptake. In a 120 h atmospheric-pressure lifetime test, the ordered mesoporous 10N1FOMA catalyst showed significant enhancement in both antisintering and anticoking properties in comparison with the unordered mesoporous 10N1FA, mainly because of the confinement effect of the mesopore channels, the weak acidity of ordered mesoporous alumina support, and the smaller Ni particle size (

A series of MnOx-promoted Ni catalysts supported on Si waste contact mass (W) modified by Al2O3 were successfully prepared by the deposition-precipitation method for CO methanation. Compared with the Ni catalysts directly supported on W, Ni/Al2O3-Si and MnOx-promoted Ni-MnOx/Al2O3-Si catalysts exhibited much better catalytic performance for CO methanation, particularly the latter, which exhibited the least decrease in CO conversion (1%) and lowest carbon deposit (0.3 wt %) in a 110 h lifetime test. The structural characterizations showed the highest Ni dispersion and highest oxygen vacancy concentration in the Ni-MnOx/Al2O3-Si catalyst. The added Al2O3 improves the dispersion of Ni, and the MnOx promoter can restrain the sintering and aggregation of Ni particles during the process of reduction and reaction at high temperatures and provides more oxygen vacancies, which is conducive to the removal of carbonaceous species on the :catalyst surface for anticoking.

We report in situ growth of mesoporous Mn0.5Co0.5Fe2O4 (MCFO) nanospheres on graphene to form MCFO/graphene nanocomposites by a facile solvothermal method. In the synthesis, Mn(CH3COO)2, Co(CH3COO)2, and FeCl3 were used as the metal precursors and CH3COOK, CH3COOC2H5, and HOCH2CH2OH as the mixed solvent. The obtained MCFO nanospheres (50–200 nm) were composed of small nanoparticles (5–15 nm), and the graphene surface acted as the nucleation sites in growing MCFO nanospheres. Compared with the bare MCFO nanospheres and the MCFO nanospheres physically mixed with graphene, the MCFO/graphene nanocomposite with 2.1 wt % graphene as anode material in Li ion batteries showed a significantly enhanced electrochemical performance with high lithium storage capacity and excellent cycling stability. This is because the introduced graphene can prevent the aggregation of nanospheres and provides a pathway for excellent Li+ ion diffusion and electronic conduction. This work opens a way for facile fabrication of metal oxi...

We report the application of partially reduced CuO nanoparticles as Cu-based catalysts for dimethyldichlorosilane (M2) synthesis via the Rochow reaction. The CuO nanoparticles (50–100 nm) were synthesized by a simple precipitation method and partially reduced in a H2/N2 mixture gas to obtain the Cu-based catalyst containing different Cu species of CuO, Cu2O, and Cu. It was found that the composition of the samples could be tailored by varying the volume ratio of H2/N2 at the given reduction temperature and time. Compared to the synthesized CuO and Cu nanoparticles, as well as the commercial CuO microparticles, these multicomponent Cu-based catalysts, particularly for the CuO–Cu2O–Cu catalyst, showed much higher M2 selectivity and Si conversion in the Rochow reaction. The enhanced catalytic performance is attributed to the smaller particle size and the synergistic effect among the different components. The work would help to develop novel ternary Cu-based catalysts for organosilane synthesis.

We report the preparation and characterization of Ni nanoparticles supported on barium hexaaluminate (BHA) as CO methanation catalysts for the production of synthetic natural gas (SNG). BHA with a high thermal stability was synthesized by a coprecipitation method using aluminum nitrate, barium nitrate, and ammonium carbonate as the precursors. The Ni catalysts supported on the BHA support (Ni/BHA) were prepared by an impregnation method. X-ray diffraction, nitrogen adsorption, transmission electron microscopy, thermogravimetric analysis, H2 temperature-programmed reduction, O2 temperature-programmed oxidation, NH3 temperature-programmed desorption, and X-ray photoelectron spectroscopy are used to characterize the samples. The CO methanation reaction was carried out at pressures of 0.1 and 3.0 MPa, weight hourly space velocities (WHSVs) of 30 000, 120 000, and 240 000 mL·g–1·h–1, with a H2/CO feed ratio of 3, and in the temperature range 300–600 °C. The results show that although the BHA support has a rela...

CO methanation reaction over the Ni/Al2O3 catalysts for synthetic natural gas production was systematically investigated by tuning a number of parameters, including using different commercial Al2O3 supports and varying NiO and MgO loading, calcination temperature, space velocity, H2/CO ratio, reaction pressure, and time, respectively. The catalytic performance was greatly influenced by the above-mentioned parameters. Briefly, a large surface area of the Al2O3 support, a moderate interaction between Ni and the support Al2O3, a proper Ni content (20 wt %), and a relatively low calcination temperature (400 °C) promoted the formation of small NiO particles and reducible β-type NiO species, which led to high catalytic activities and strong resistance to the carbon deposition, while addition of a small amount of MgO (2 wt %) could improve the catalyst stability by reducing the carbon deposition; other optimized conditions that enhanced the catalytic performance included high reaction pressure (3.0 MPa), high H2...

Mesoporous Cu2O (MP-Cu2O) microspheres were prepared via a facile template-free hydrothermal synthesis in the open system, in which copper acetate was used as the copper precursor and glucose as a reducing agent. The synthesis conditions and catalytic property of MP-Cu2O for dimethyldichlorosilane synthesis via the Rochow reaction were investigated, and the formation mechanism of MP-Cu2O microspheres was proposed. The samples were characterized by nitrogen adsorption, X-ray diffraction, temperature-programmed reduction, thermogravimetric analysis, transmission electron microscopy, and scanning electron microscopy. It was found that the synthesis conditions such as reaction temperature, time, and reactant amount added have a significant effect on the morphology and pore structure of MP-Cu2O microspheres, and MP-Cu2O microspheres were formed through assembly of Cu2O nanoparticles. MP-Cu2O microspheres with a surface area of 65.8 m(2)/g, pore size of 26.7 nm, and a diameter of 400-700 nm were obtained under the optimized condition. As compared to the nonporous Cu2O microspheres, MP-Cu2O microspheres showed a better catalytic performance in dimethyldichlorosilane synthesis due to their developed pore structure and high surface area, which allow larger contact interface among the reaction gas, solid catalyst, and the solid reactant, together with enhanced mass transport. The work would be helpful for developing novel structured copper catalysts for organosilane synthesis and for understanding the catalytic mechanism.

Carbon nanospheres (CNSs) with a diameter of less than 100 nm, containing nitrogen-functional groups, and turbostratic structure were prepared by carbonizing polypyrrole nanospheres (PNSs), which were synthesized by polymerization of pyrrole under ultrasonic conditions in the presence of dual surfactants and catalyst. The materials were characterized by X-ray diffraction, thermogravimetric analysis, field-emission transmission electron microscope, field-emission scanning electron microscope, Raman spectroscope, nitrogen adsorption, and X-ray photoelectron spectroscope. In addition, the electrochemical properties of the CNSs as anode materials in lithium-ion batteries were evaluated. It was found that the use of ultrasonication is a simple and reproducible method for the synthesis of monodisperse PNSs. The CNSs displayed a higher specific capacity than the carbon spheres derived from sucrose and a higher rate capability than commercial mesophase carbon microbeads.