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Jing, Shou-Yong; Liu, Lin; Huang, N. K.; Zhang, Jin; Lü, Yong

doi:10.1023/a:1006710808718

Cited by 52 publications

(8 citation statements)

References 4 publications

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“…This could be attributed to the presence of MgNiO2 species, and might indicate the formation of NixMg(1-x)O2 solid solutions. In addition, another broad peak around 45.1º can be observed for the sample with 13.0%Mg, which could be related to the presence of NiAl2O4 and/or MgAl2O4 in the samples, according to the literature 10,[27][28][29][30][31][32][33][34][35] .…”

Section: Catalysts Characterizationmentioning

confidence: 59%

Magnesium as Promoter of CO₂ Methanation on Ni-Based USY Zeolites

et al. 2017

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CO2 methanation was studied over Ni-Mg-USY zeolite catalysts. Mg was added by incipient wetness impregnation and ion-exchange. Whatever the Mg incorporation method used, Mg is able to improve the performances of the Ni-zeolite catalysts. Magnesium impregnation at lower contents (below 2.5%) over a 5%Ni/zeolite leads to an enhancement of the CO2 conversion into methane of 15% at 350-450ºC, probably due to the induced increase of the Ni particles dispersion, as well as to the possible activation of CO2 on the defects present on the MgO surface. At higher Mg contents, the stronger interaction between Ni and Mg oxides, leading to the formation of NiO-MgO solid solutions, seem to reduce the reducibility of the Ni species, decreasing the amount of nickel active sites available, and, so, the catalytic performances. Furthermore, important improvements of the catalytic performances (CO2 conversion and CH4 selectivity increased around 20% at 350-450ºC) were also found for the Mg-exchanged 5%Ni/zeolite. The results are comparable to those obtained by impregnation, but lower Mg contents are required. The enhanced activation of CO2 on Mg 2+ , the more dispersed Ni particles on the support, as well as the enhanced Ni reducibility when compared to the impregnated catalysts, can explain the observed results. The beneficial effect of the Mg addition both by impregnation and ion-exchange was also observed for samples containing higher amounts of Ni, the best sample remaining stable after 10h under reaction conditions. Thus, Mg could be an interesting promoter for the CO2 methanation over Ni-zeolite catalysts.

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Section: Catalysts Characterizationmentioning

confidence: 59%

Magnesium as Promoter of CO₂ Methanation on Ni-Based USY Zeolites

et al. 2017

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“…For Pd/Al 2 O 3 catalyst, Pd diffractions were not found since its loading was low (0.2%) and only Al 2 O 3 peaks were visible (Figure 6b). Pd/MgO/Al 2 O 3 (Figure 6c) showed characteristic diffraction peaks shifted to the direction in lower values of 2θ due to the substitution of Al 3+ by Mg 2+ [23]. Pd/CaO/Al 2 O 3 (Figure 6d) showed no diffraction peaks of CaO, indicating the high dispersion of CaO in the corresponding catalyst.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Stability of CaO and/or La2O3 Promoted Pd/Al2O3 Egg-Shell Catalysts in Partial Oxidation of Methane to Syngas

Wang

et al. 2013

Molecules

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An egg-shell Pd/Al 2 O 3 catalyst showed higher activity than a regular Pd/Al 2 O 3 catalyst in the partial oxidation of methane to syngas, but a common problem of this reaction is the catalyst deactivation on stream. We attempted to modify the egg-shell catalyst via impregnation with some metal oxide additives. Although the addition of MgO did not show any beneficial effect, the addition of CaO and/or La 2 O 3 significantly improved the stability due to the suppression of carbon deposition and phase transformation of the Al 2 O 3 support. The catalysts were characterized by X-ray diffraction (XRD), N 2 adsorption-desorption, and thermogravimetric analysis (TGA).

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“…Despite the general trend, experimental data seemed to experience a slight positive deviation from theoretical path. This behaviour was already observed by other authors [25,31,32], not giving clear explanation about the phenomenon responsible for the behaviour. On the other hand, no calcination temperature effect was observed in lattice parameter.…”

Section: Crystalline Structurementioning

confidence: 53%

Effect of secondary thermal treatment on crystallinity of spinel-type Co(Cr,Al)2O4 pigments synthesized by solution combustion route

Gilabert

Gómez-Tena

Sanz

et al. 2018

Journal of Non-Crystalline Solids

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The effect of a post-synthesis thermal treatment on CoCr 2-2Y Al 2Y O 4 (0.0≤Y≤1.0) ceramic pigments synthesized by Solution Combustion Synthesis (SCS) has been studied. Assynthesized SCS pigments were treated at two different calcination temperatures (800 ºC and 1000 ºC) to study changes in mineralogy, microstructure and thermal behaviour, as well as their effect over the colouring power. Spinel-type Fd-3m crystalline structure was developed in all cases. Nevertheless, crystallinity parameters were highly affected by both analysed processing parameters: composition (Y) and post-synthesis calcination temperature (T c). A Cr(III) enrichment along with T c increase favoured ion rearrangement to promote sample crystallization and crystallite growth. Fast kinetics of SCS makes Al-rich spinels with transition metals difficult to be synthesized. The application of a secondary thermal treatment resulted in a favourable evolution towards a well-crystallized structure. Lattice parameter did not seem to be affected by T c , although it evolved indeed with composition. From a microstructural point of view, as-synthesized pigments were foamy, with a very low bulk density and nanometric grain size. After the thermal treatment, larger grain sizes were obtained, especially for the samples richer in Al and treated at higher T c. All pigments developed intense colours in a transparent glaze without showing heterogeneities, indicating a stable behaviour against glazing process. Glaze colour evolved from green to perfectly blue shades, indicating an important dependence on composition. Nevertheless, colouring power seemed to be rather affected by calcination process.

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Cited by 52 publications

References 4 publications

Magnesium as Promoter of CO₂ Methanation on Ni-Based USY Zeolites

Magnesium as Promoter of CO₂ Methanation on Ni-Based USY Zeolites

Enhanced Stability of CaO and/or La2O3 Promoted Pd/Al2O3 Egg-Shell Catalysts in Partial Oxidation of Methane to Syngas

Effect of secondary thermal treatment on crystallinity of spinel-type Co(Cr,Al)2O4 pigments synthesized by solution combustion route

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Untitled

Cited by 52 publications

References 4 publications

Magnesium as Promoter of CO2 Methanation on Ni-Based USY Zeolites

Magnesium as Promoter of CO2 Methanation on Ni-Based USY Zeolites

Enhanced Stability of CaO and/or La2O3 Promoted Pd/Al2O3 Egg-Shell Catalysts in Partial Oxidation of Methane to Syngas

Effect of secondary thermal treatment on crystallinity of spinel-type Co(Cr,Al)2O4 pigments synthesized by solution combustion route

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Magnesium as Promoter of CO₂ Methanation on Ni-Based USY Zeolites

Magnesium as Promoter of CO₂ Methanation on Ni-Based USY Zeolites