Effect of Citric Acid on MoO3/Al2O3 Catalysts for Sulfur-Resistant Methanation

Dajun, Meng; Wang, Baowei; Yu, Wenxia; Wang, Weihan; Li, Zhenhua; Ma, Xinbin

doi:10.3390/catal7050151

Cited by 21 publications

(7 citation statements)

References 29 publications

(29 reference statements)

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“…Reduction of pure MoO 3 occurs at 767 (corresponding to MoO 3 → MoO 2 ) and 997 °C (MoO 2 → Mo). A minor shoulder to the first peak at 797 °C (corresponding to Mo 4 O 11 formed by the reduction of MoO 3 ) was also reported. , In the case of Mo/ZrO 2 , the two reduction peaks observed at 400–420 and 800–940 °C were assigned to octahedral and tetrahedral molybdenum oxide species, respectively. , In the present study, (for 4Pt-8MoO x /Al 2 O 3 ) the reduction peak of octahedral molybdenum oxide had shifted to 173 °C because of its intimate contact with platinum. Zhu et al reported a low-temperature reduction peak at 320 °C and a high-temperature peak above 800 °C for Pt-5WO x /Al2O 3 , attributable to reduction of WO 3 to WO 2.9 and WO 2 , respectively.…”

Section: Resultssupporting

confidence: 77%

Metal Oxide-Promoted Hydrodeoxygenation Activity of Platinum in Pt-MO_x/Al₂O₃Catalysts for Green Diesel Production

Janampelli

Srinivas

2018

Energy Fuels

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Catalytic deoxygenation of fatty acids into renewable hydrocarbons (green diesel) was investigated over 4Pt-8MO x /Al2O3 (M = Mo, Re, W, and Sn) catalysts prepared by the wet impregnation method. Platinum deposited on MO x -modified γ-Al2O3 showed higher catalytic hydrodeoxygenation activity than that of the “neat” Pt/Al2O3 catalyst. The promotional effect of metal oxides (MO x ) decreased in the following order: MoO x > ReO x > WO x > SnO x . Characterization studies revealed that metal oxides affect the textural and electronic properties of Pt. Supported Pt facilitated the reduction of these metal oxides. Synergy and electronic contact between Pt and MO x determined the catalytic deoxygenation performance. Fatty acid conversion increased with increasing metallic nature (decreasing binding energy) of Pt. Hydrodeoxygenation product selectivity correlated with the extent of metal oxide reduction. Among the catalysts, 4Pt-8MoO x /Al2O3 had the optimum dispersion, electron-rich Pt, and reduced Mo5+ species, enabling quantitative conversion of oleic acid with 93.5% octadecane selectivity at a temperature as low as 220 °C and 20 bar hydrogen pressure. Metal oxide switched the mechanism of deoxygenation from decarbonylation/decarboxylation to hydrodeoxygenation. Fatty acids, methyl oleate, and vegetable oil were deoxygenated with equal efficiency over this catalyst. Catalysts were reusable in recycling studies only at higher temperature (320 °C) and not at lower temperature (260 °C), perhaps due to strong sticking of reactant molecules at lower temperature on the catalyst surface than at higher temperature.

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Section: Resultssupporting

confidence: 77%

Metal Oxide-Promoted Hydrodeoxygenation Activity of Platinum in Pt-MO_x/Al₂O₃Catalysts for Green Diesel Production

Janampelli

Srinivas

2018

Energy Fuels

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“…The X-ray Diffraction (XRD) patterns of Mo-Al and Pd/Mo-Al catalysts with various palladium contents (1-4 wt%) are shown in Figure 1A, and Figure 1B shows the enlarged view XRD pattern of Mo-Al catalyst. For all catalysts, the diffraction peaks of γ-Al2O3 were identified at 2θ = 45.8° and 67.1° [29] while the peaks at 2θ = 23.4° and 25.7° were assigned to the crystalline MoO3 phase [30]. In addition, other peaks at 2θ = 20.7°, 22.0°, 23.4°, and 25.7° were identified, which are attributed to the Al2(MoO4)3 phase.…”

Section: Structural Characterizations Of the Catalystsmentioning

confidence: 90%

“…After incorporation of palladium into catalysts, the Brunauer-Emmett-Teller (BET) surface area, the average pore volume, and the pore size of all catalysts were found to be smaller than the original Mo-Al catalyst. This change is obvious because of the impregnation of Pd on the support that would block the micropores of the catalysts [30]. Temperature programmed desorption (TPD) experiments of γ-Al 2 O 3 , Mo-Al and 1-4 wt% Pd/Mo-Al catalysts were performed to determine the amount and strength of acid sites.…”

Section: Physicochemical Properties Of Catalystsmentioning

confidence: 99%

Toward the Sustainable Synthesis of Propanols from Renewable Glycerol over MoO3-Al2O3 Supported Palladium Catalysts

Samudrala

Bhattacharya

2018

Catalysts

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The catalytic conversion of glycerol to value-added propanols is a promising synthetic route that holds the potential to overcome the glycerol oversupply from the biodiesel industry. In this study, selective hydrogenolysis of 10 wt% aqueous bio-glycerol to 1-propanol and 2-propanol was performed in the vapor phase, fixed-bed reactor by using environmentally friendly bifunctional Pd/MoO3-Al2O3 catalysts prepared by wetness impregnation method. The physicochemical properties of these catalysts were derived from various techniques such as X-ray diffraction, NH3-temperature programmed desorption, scanning electron microscopy, 27Al NMR spectroscopy, surface area analysis, and thermogravimetric analysis. The catalytic activity results depicted that a high catalytic activity (>80%) with very high selectivity (>90%) to 1-propanol and 2-propanol was obtained over all the catalysts evaluated in a continuously fed, fixed-bed reactor. However, among all others, 2 wt% Pd/MoO3-Al2O3 catalyst was the most active and selective to propanols. The synergic interaction between the palladium and MoO3 on Al2O3 support and high strength weak to moderate acid sites of the catalyst were solely responsible for the high catalytic activity. The maximum glycerol conversion of 88.4% with 91.3% selectivity to propanols was achieved at an optimum reaction condition of 210 ∘ C and 1 bar pressure after 3 h of glycerol hydrogenolysis reaction.

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“…04-0850). There is no reflection of Mo, indicating that Mo has excellent dispersion on the surface of the support . This result suggests that when Ni and Mo are jointly impregnated, a new highly dispersed (or perhaps less crystalline) structure may be formed …”

Section: Resultsmentioning

confidence: 97%

“…There is no reflection of Mo, indicating that Mo has excellent dispersion on the surface of the support. 32 This result suggests that when Ni and Mo are jointly impregnated, a new highly dispersed (or perhaps less crystalline) structure may be formed. 33 The surface morphology of the catalysts were analyzed by transmission electron microscopy (TEM) (Figure 4).…”

Section: Industrial and Engineeringmentioning

confidence: 99%

Effect of Mo Addition on the Performance of Ni-Based Methanation Catalysts Supported by Halloysites

Meng

Xin

et al. 2023

Ind. Eng. Chem. Res.

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Ni-based halloysite methanation catalysts with various Mo contents were prepared by using halloysites as supports, and it was used to catalyze the methanation reaction. The addition of Mo can strengthen the interaction between Ni and the halloysite, preventing the active component Ni from aggregating into the larger particles during the reaction, which can improve the catalyst activity and life. At the same time, the electron donation of the Mo atom can rise the electron density around the nickel atom and facilitate the dissociation of carbon monoxide on the Ni surface, which can improve the activity of the reaction under low temperature. Among them, the 6Mo10Ni/eHNTs catalyst has the best activity at 350 °C. The conversion of CO achieves 100% and the yield of CH 4 reaches 99.7%. At 300 °C, the CO conversion rate is 100%, and the CH 4 yield is 97%, which is the same as the activity of 10Ni/eHNTs without Mo at 350 °C, i.e., the low temperature activity is improved with the addition of Mo. At the same time, the addition of Mo enhances the anti-sintering property and resistance to the carbon deposition of the catalysts. This work shows the possibility for the industrial application of the methanation catalyst using halloysites as the support.

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Effect of Citric Acid on MoO3/Al2O3 Catalysts for Sulfur-Resistant Methanation

Cited by 21 publications

References 29 publications

Metal Oxide-Promoted Hydrodeoxygenation Activity of Platinum in Pt-MO_x/Al₂O₃Catalysts for Green Diesel Production

Metal Oxide-Promoted Hydrodeoxygenation Activity of Platinum in Pt-MO_x/Al₂O₃Catalysts for Green Diesel Production

Toward the Sustainable Synthesis of Propanols from Renewable Glycerol over MoO3-Al2O3 Supported Palladium Catalysts

Effect of Mo Addition on the Performance of Ni-Based Methanation Catalysts Supported by Halloysites

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Effect of Citric Acid on MoO3/Al2O3 Catalysts for Sulfur-Resistant Methanation

Cited by 21 publications

References 29 publications

Metal Oxide-Promoted Hydrodeoxygenation Activity of Platinum in Pt-MOx/Al2O3Catalysts for Green Diesel Production

Metal Oxide-Promoted Hydrodeoxygenation Activity of Platinum in Pt-MOx/Al2O3Catalysts for Green Diesel Production

Toward the Sustainable Synthesis of Propanols from Renewable Glycerol over MoO3-Al2O3 Supported Palladium Catalysts

Effect of Mo Addition on the Performance of Ni-Based Methanation Catalysts Supported by Halloysites

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Metal Oxide-Promoted Hydrodeoxygenation Activity of Platinum in Pt-MO_x/Al₂O₃Catalysts for Green Diesel Production

Metal Oxide-Promoted Hydrodeoxygenation Activity of Platinum in Pt-MO_x/Al₂O₃Catalysts for Green Diesel Production