Preparation and characterization of Al2O3–MgO catalytic supports modified with lithium

Escobar‐Alarcón, L.; Klimova, Tatiana; Escobar-Aguilar, J.; Romero, S.; Morales-Ramírez, C.; Solís-Casados, Dora Alicia

doi:10.1016/j.fuel.2012.10.013

Cited by 17 publications

(8 citation statements)

References 20 publications

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“…The Sm 2 O 3 NPs are more basic than the TbO x NPs and the n-MgO support, and the broad peaks reveal that both monodentate and bidentate carbonates are present on the surface. Compared with the Sm 2 O 3 NPs, more CO 2 is bound to the surface of the Li/n-MgO, and the majority of the species on the surface are monodentate carbonates associated with the lithium …”

Section: Resultsmentioning

confidence: 99%

“…DRIFTS background spectra collected after outgassing at 450 °C for reference compounds and lithium-doped and undoped REO/n-MgO. Dashed lines mark positions for different carbonate species: blue dashed line, monodentate carbonates on MgO; orange dashed line, monodentate carbonate interactions with Li species; red dotted/dashed line, bidentate carbonates on Sm 2 O 3 ; and pink dashed line, monodentate carbonates on Sm 2 O 3 …”

Section: Resultsmentioning

confidence: 99%

“…the surface of the Li/n-MgO, and the majority of the species on the surface are monodentate carbonates associated with the lithium. 48 The DRIFTS spectra with a KBr background subtraction obtained from the REO/n-MgO and Li-REO/n-MgO catalysts after heat treatment at 450 °C are also shown in Figure 11. The spectra from the Sm 2 O 3 /n-MgO and TbO x /n-MgO catalysts are similar and resemble the spectra obtained from the pure n-MgO support.…”

Section: Xrd Analysismentioning

confidence: 92%

“…These peaks are most likely due to carbonates chemisorbed on lithium because the peaks match well with data obtained on a lithium-doped Al 2 O 3 -MgO catalyst system. 48 As for the n-MgO support, a temperature of 250 °C appears to be sufficient to remove the bicarbonates and yield more strongly bound mono-and bidentate carbonate species. In both cases, the amount of CO 2 adsorbed on the surface is higher at 250 °C compared with adsorption at 50 °C.…”

Section: Xrd Analysismentioning

confidence: 99%

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Effects of Li Doping on MgO-Supported Sm₂O₃ and TbO_x Catalysts in the Oxidative Coupling of Methane

et al. 2014

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Rare earth oxides (REOs), particularly the sesquioxides, such as Sm 2 O 3 and La 2 O 3 , have been investigated as promising catalysts in the oxidative coupling of methane (OCM). Much less attention has been paid to the reducible REOs because they are expected to give oxidation products, such as CO and CO 2 (CO x ), rather than the desirable ethane and ethylene (C 2+ ). Because Li addition can improve the performance of Sm 2 O 3 in the OCM reaction and Li/MgO is commonly used as a reference OCM catalyst, the effects of lithium addition to a reducible oxide, TbO x , were investigated in detail in this study and compared with a Sm 2 O 3 catalyst, which is the best single component OCM catalyst. Because of the well-documented volatility of lithium under OCM conditions, particularly for the Li/MgO system, the stability of lithiumdoped samaria and terbia catalysts was examined as a function of preparation methods in this study. As expected, terbia supported on nanoparticle magnesia (n-MgO) is not a very active or selective OCM catalyst, and most of the observed selectivity toward C 2+ products is likely due to the n-MgO support. In contrast, Li-doped TbO x /n-MgO prepared using a coimpregnation method yields a highly active and selective catalyst. The Li-TbO x /n-MgO catalyst yields the same methane conversion as pure Sm 2 O 3 , and has a higher C 2+ selectivity than the Li-Sm 2 O 3 /n-MgO catalyst. The stability of the Li-TbO x /n-MgO catalyst is also higher than that of the Li-Sm 2 O 3 /n-MgO catalyst, and the loss of activity for the lithium-doped terbia catalyst appears to be the same as for the undoped Sm 2 O 3 /n-MgO catalyst (and undoped TbO x /n-MgO). The characterization data indicate stronger interactions between Li and TbO x than between Li and Sm 2 O 3 , which may explain the higher stability of the Li-TbO x /n-MgO catalysts. There are also indications that Li enters the TbO x lattice and reduces TbO 1.81 , to Tb 2 O 3 during reaction, which can explain the higher C 2+ selectivity compared with undoped TbO x /n-MgO. Furthermore, the Li-TbO x /n-MgO catalyst in this study is active at lower temperatures (600−700 °C) than typically used in the OCM (around 800 °C). Therefore, the Li-TbO x / n-MgO catalysts have potential to be very effective OCM catalysts, even though undoped TbO x /n-MgO catalysts are more selective toward CO x than C 2+ products.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Xrd Analysismentioning

confidence: 92%

Section: Xrd Analysismentioning

confidence: 99%

See 2 more Smart Citations

Effects of Li Doping on MgO-Supported Sm₂O₃ and TbO_x Catalysts in the Oxidative Coupling of Methane

et al. 2014

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“…This can be mitigated using more neutral supports such as silica–alumina-supported noble metals or nonacidic supports. − Works using supports such as zirconium-doped mesoporous silica have been used in the hydrogenation of tetralin, highlighting very active catalysis at 350 °C and 6.0 MPa hydrogen pressure . Research has also recently been undertaken to assess the impact of both noble and group VI metals over basic carriers in both HYD and hydrodesulfurization (HDS) reactions. ,− It has been shown that a 2 wt % concentration of alkaline-earth metals dispersed over the conventional acidic support led to greater activity of platinum during the hydrogenation reaction of naphthalene . The works in Escobar et al added to previous experimental work wherein basic supports were investigated and hypothesized to interact with metallic Ru nanoparticles, producing dual-site heterolytic hydrogen splitting and surface ionic hydrogenation pathways .…”

Section: Introductionmentioning

confidence: 99%

Comparative Study on the Hydrogenation of Naphthalene over Both Al₂O₃-Supported Pd and NiMo Catalysts against a Novel LDH-Derived Ni-MMO-Supported Mo Catalyst

2021

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Naphthalene hydrogenation was studied over a novel Ni–Al-layered double hydroxide-derived Mo-doped mixed metal oxide (Mo-MMO), contrasted against bifunctional NiMo/Al2O3, and Pd-doped Al2O3 catalysts, the latter of which with Pd loadings of 1, 2, and 5 wt %. Reaction rate constants were derived from a pseudo-first-order kinetic pathway describing a two-step hydrogenation pathway to tetralin (k 1) and decalin (k 2). The Mo-MMO catalyst achieved comparable reaction rates to Pd2%/Al2O3 at double concentration. When using Pd5%/Al2O3, tetralin hydrogenation was favored over naphthalene hydrogenation culminating in a k 2 value of 0.224 compared to a k 1 value of 0.069. Ni- and Mo-based catalysts produced the most significant cis-decalin production, with Mo-MMO culminating at a cis/trans ratio of 0.62 as well as providing enhanced activity in naphthalene hydrogenation compared to NiMo/Al2O3. Consequently, Mo-MMO presents an opportunity to generate more alkyl naphthenes in subsequent hydrodecyclization reactions and therefore a higher cetane number in transport fuels. This is contrasted by a preferential production of trans-decalin observed when using all of the Al2O3-supported Pd catalysts, as a result of octalin intermediate orientations on the catalyst surface as a function of the electronic properties of Pd catalysts.

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Enhancing the Electrochemical Performance of Ternary Metallic Phosphates for High‐Energy and Anti‐Self‐Discharge Supercapacitors through Binder Optimization

et al. 2023

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Supercapacitors have proven themselves as a subject of interest over the years for energy storage. As a result, it is not surprising that significant effort has been put into supercapacitor research. However, a device with all desirable properties still needs to be developed, requiring special attention. A simple synthesis of porous magnesium niobium silver phosphate (Mg3Nb1−xAgx(PO4)3) nanocomposites is presented using a novel mixed solvent solution and a hydrothermal method. The MgNbAgPO4 anode with an interconnected porous structure not only offers a large number of active sites for divalent ion trapping but also improves charge transfer kinetics. As a result, the Mg3Nb1−xAgx(PO4)3 anode has a high specific capacity of 958 C g−1 using a binder‐free electrode and better rate capability. The full‐cell design is also built with Mg3Nb1−xAgx(PO4)3 and activated carbon (AC). The hierarchical pore structure and appropriate functional groups Mg3Nb1−xAgx(PO4)3 anode deliver a maximum energy density of 57 Wh kg−1, a high power density of 1200 kW kg−1, and anti‐self‐discharge solid behavior. The analysis of the charge storage mechanism suggests that Mg3Nb1−xAgx(PO4)3//AC supercapattery involves adsorption/desorption and Faradic reactions to store charge. This study opens the path for high‐performance Mg3Nb1−xAgx(PO4)3 electrode and gives a better knowledge of charge storage.

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Preparation and characterization of Al2O3–MgO catalytic supports modified with lithium

Cited by 17 publications

References 20 publications

Effects of Li Doping on MgO-Supported Sm₂O₃ and TbO_x Catalysts in the Oxidative Coupling of Methane

Effects of Li Doping on MgO-Supported Sm₂O₃ and TbO_x Catalysts in the Oxidative Coupling of Methane

Comparative Study on the Hydrogenation of Naphthalene over Both Al₂O₃-Supported Pd and NiMo Catalysts against a Novel LDH-Derived Ni-MMO-Supported Mo Catalyst

Enhancing the Electrochemical Performance of Ternary Metallic Phosphates for High‐Energy and Anti‐Self‐Discharge Supercapacitors through Binder Optimization

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Preparation and characterization of Al2O3–MgO catalytic supports modified with lithium

Cited by 17 publications

References 20 publications

Effects of Li Doping on MgO-Supported Sm2O3 and TbOx Catalysts in the Oxidative Coupling of Methane

Effects of Li Doping on MgO-Supported Sm2O3 and TbOx Catalysts in the Oxidative Coupling of Methane

Comparative Study on the Hydrogenation of Naphthalene over Both Al2O3-Supported Pd and NiMo Catalysts against a Novel LDH-Derived Ni-MMO-Supported Mo Catalyst

Enhancing the Electrochemical Performance of Ternary Metallic Phosphates for High‐Energy and Anti‐Self‐Discharge Supercapacitors through Binder Optimization

Contact Info

Product

Resources

About

Effects of Li Doping on MgO-Supported Sm₂O₃ and TbO_x Catalysts in the Oxidative Coupling of Methane

Effects of Li Doping on MgO-Supported Sm₂O₃ and TbO_x Catalysts in the Oxidative Coupling of Methane

Comparative Study on the Hydrogenation of Naphthalene over Both Al₂O₃-Supported Pd and NiMo Catalysts against a Novel LDH-Derived Ni-MMO-Supported Mo Catalyst