scholarly journals Low Temperature Methanation of CO2 on High Ni Content Ni-Ce-ZrOδ Catalysts Prepared via One-Pot Hydrothermal Synthesis

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 32 ◽  
Author(s):  
Vissanu Meeyoo ◽  
Noppadol Panchan ◽  
Nat Phongprueksathat ◽  
Atsadang Traitangwong ◽  
Xinpeng Guo ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Low Temperature ◽  
High Surface ◽  
Oxygen Species ◽  
Co2 Conversion ◽  
One Pot ◽  
Co2 Methanation ◽  
Surface Areas ◽  
Ni Content ◽  
Methane Selectivity

Ni-Ce-Zr-Oδ catalysts were prepared via one-pot hydrothermal synthesis. It was found that Ni can be partially incorporated into the Ce-Zr lattice, increasing surface oxygen species. The catalysts possess high surface areas even at high Ni loadings. The catalyst with Ni content of 71.5 wt.% is able to activate CO2 methanation even at a low temperature (200 °C). Its CO2 conversion and methane selectivity were reported at 80% and 100%, respectively. The catalyst was stable for 48 h during the course of CO2 methanation at 300 °C. Catalysts with the addition of medium basic sites were found to have better catalytic activity for CO2 methanation.

Synthesis and Characterization of Aerogel-derived Cation-substituted Hexaaluminates

1996 ◽  
Vol 457 ◽  
Author(s):  
Lin-chiuan Yan ◽  
Levi T. Thompson
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Catalytic Combustion ◽  
High Surface ◽  
High Surface Area ◽  
Synthesis And Characterization ◽  
New Methods ◽  
Surface Areas ◽  
Different Characteristics

ABSTRACTNew methods have been developed for the synthesis of high surface area cation-substituted hexaaluminates. These materials were prepared by calcining high temperature (ethanol extraction) or low temperature (CO2 extraction) aerogels at temperatures up to 1600°C. Cation-substituted hexaaluminates have emerged as promising catalysts for use in high temperature catalytic combustion. In comparing unsubstituted and cation-substituted hexaaluminates, we found that the phase transformations were much cleaner for the cation-substituted materials. BaCO3 and BaAl2O4 were intermediates during transformation of the unsubstituted materials, while the cation-substituted materials transformed directly from an amorphous phase to crystalline hexaaluminate. Moreover, the presence of substitution cations caused the transformation to occur at lower temperatures. Mn seems to be a better substitution cation than Co since the Mn-substituted materials exhibited higher surface areas and better heat resistances than the Co-substituted materials. The low temperature aerogel-derived materials possessed quite different characteristics from the high temperature aerogel-derived materials. For example, phase transformation pathways were different.

Enhanced low-temperature activity for CO2 methanation over Ru doped the Ni/CexZr(1−)O2 catalysts prepared by one-pot hydrolysis method

2018 ◽  
Vol 43 (14) ◽  
pp. 7179-7189 ◽  
Author(s):  
Xingfu Shang ◽  
Digu Deng ◽  
Xueguang Wang ◽  
Weidong Xuan ◽  
Xiujing Zou ◽  
...  
Keyword(s):  
Low Temperature ◽  
One Pot ◽  
Co2 Methanation ◽  
Hydrolysis Method

scholarly journals One-Pot Cu/TiO2 Nanoparticles Synthesis for Trans-Ferulic Acid Conversion into Vanillin

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3985 ◽  
Author(s):  
Paulette Gómez-López ◽  
Noelia Lázaro ◽  
Clemente G. Alvarado-Beltrán ◽  
Antonio Pineda ◽  
Alina M. Balu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ferulic Acid ◽  
Metallic Nanoparticles ◽  
High Surface ◽  
Hydrothermal Process ◽  
Atomic Ratio ◽  
Homogeneous Distribution ◽  
One Pot ◽  
Surface Areas ◽  
Cost Efficient

In this study, the co-synthesis of TiO2 and Cu metallic nanoparticles obtained via one-pot cost-efficient hydrothermal process has been addressed. Different nanocatalysts with Cu contents were characterized by X-ray diffraction, nitrogen porosimetry, scanning electron microscopy, and transmission electron microscopy. The TiO2 and Cu metallic nanoparticles were synthesized with copper loading up to one (Cu/Ti atomic ratio). Synthesized catalysts exhibited pore sizes in the mesoporous range and high surface areas above 150 m2/g. The particle size for TiO2 presented a homogeneous distribution of approximately 8 nm, moreover, Cu nanoparticles varied from 12 to >100 nm depending on the metal loading. The nanostructured materials were successfully tested in the conversion of trans-ferulic acid into vanillin under sustainable conditions, achieving the best performance for 0.3 Cu/Ti atomic ratio (70% vanillin yield).

scholarly journals Methanation of CO2 Using MIL-53-Based Catalysts: Ni/MIL-53–Al2O3 versus Ni/MIL-53

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1412
Author(s):  
Oana Grad ◽  
Gabriela Blanita ◽  
Mihaela D. Lazar ◽  
Maria Mihet
Keyword(s):  
Prolonged Exposure ◽  
Reaction Medium ◽  
Catalytic Performance ◽  
The Novel ◽  
Co2 Conversion ◽  
Co2 Methanation ◽  
Nanoparticle Deposition ◽  
Metallic Particles ◽  
Al2o3 Composite ◽  
Methane Selectivity

MIL-53 and the MIL-53–Al2O3 composite synthesized by a solvothermal procedure, with water as the only solvent besides CrCl3 and benzene-1,4-dicarboxylic acid (BDC), were used as catalytic supports to obtain the novel MIL-53-based catalysts Ni(10 wt.%)/MIL-53 and Ni(10 wt.%)/MIL-53–Al2O3. Ni nanoparticle deposition by an adapted double-solvent method leads to the uniform distribution of metallic particles, both smaller (≤10 nm) and larger ones (10–30 nm). MIL-53–Al2O3 and Ni/MIL-53–Al2O3 show superior thermal stability to MIL-53 and Ni/MIL-53, while MIL-53–Al2O3 samples combine the features of both MIL-53 and alumina in terms of porosity. The investigation of temperature’s effect on the catalytic performance in the methanation process (CO2:H2 = 1:5.2, GHSV = 4650 h−1) revealed that Ni/MIL-53 is more active at temperatures below 300 °C, and Ni/MIL-53–Al2O3 above 300 °C. Both catalysts show maximum CO2 conversion at 350 °C: 75.5% for Ni/MIL-53 (methane selectivity of 93%) and 88.8% for Ni/MIL-53–Al2O3 (methane selectivity of 98%). Stability tests performed at 280 °C prove that Ni/MIL-53–Al2O3 is a possible candidate for the CO2 methanation process due to its high CO2 conversion and CH4 selectivity, corroborated by the preservation of the structure and crystallinity of MIL-53 after prolonged exposure in the reaction medium.

scholarly journals Enhanced CO2 Methanation Reaction in C1 Chemistry over a Highly Dispersed Nickel Nanocatalyst Prepared Using the One-Step Melt-Infiltration Method

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 643 ◽  
Author(s):  
Eui Hyun Cho ◽  
Woohyun Kim ◽  
Chang Hyun Ko ◽  
Wang Lai Yoon
Keyword(s):  
Catalytic Performance ◽  
High Dispersion ◽  
Co2 Conversion ◽  
Co2 Methanation ◽  
Gas Treatment ◽  
Ni Content ◽  
Melt Infiltration ◽  
One Step ◽  
The One ◽  
Infiltration Method

The Paris Agreement requires the world to put the best efforts to reduce CO2 emissions, due to the global warming problems. As a promising technology corresponding to this greenhouse gas treatment, the CO2 methanation process a.k.a power to gas (PtoG), which catalytically converts CO2 into methane, has been in the limelight. To develop an efficient catalytic process, it is necessary to design a low-cost and high-efficiency catalyst for high CO2 conversion and CH4 selectivity. In this study, we have developed Ni/γ-Al2O3 catalysts by the one-step melt-infiltration method, where both aging and calcination are done in one pot. For enhancement of the catalytic activity and selectivity, sufficient Ni content (>25 wt %) and a high dispersion (<10 nm) are simultaneously required. Thus, the aging conditions of the melt-infiltration methods, e.g., time and temperature, were optimized for the high dispersion with sufficient Ni content (15–50 wt %). The catalytic performance tests were carried out under atmospheric pressure, 275 to 400 °C and gas hourly velocity (GHSV) = 25,000 h−1. And the various characteristic analyses (Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), H2-chemisorption, temperature programmed reduction (TPR), etc.) were performed to confirm the effects on the catalytic performance. As a result, based on the experiments and the characterization data, the 30 wt %-Ni catalyst (Ni particles size = 11 nm) showed the best CO2 conversion at 300 °C and the 20 wt % one having the highest Ni dispersion (Ni particles size = 8.8 nm), which showed the best intrinsic reaction rate and CH4 selectivity in the entire temperature range.

scholarly journals CO2 Methanation Using Multimodal Ni/SiO2 Catalysts: Effect of Support Modification by MgO, CeO2, and La2O3

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 443
Author(s):  
Maria Mihet ◽  
Monica Dan ◽  
Lucian Barbu-Tudoran ◽  
Mihaela D. Lazar
Keyword(s):  
Pore Structure ◽  
Silica Matrix ◽  
Co2 Conversion ◽  
Target Concentration ◽  
Co2 Methanation ◽  
Temperature Programmed ◽  
Carbon Dioxide Co2 ◽  
Methane Selectivity ◽  
Effect Of Support ◽  
Adsorption Desorption

Ni/oxide-SiO2 (oxide: MgO, CeO2, La2O3, 10 wt.% target concentration) catalyst samples were prepared by successive impregnation of silica matrix, first with supplementary oxide, and then with Ni (10 wt.% target concentration). The silica matrix with multimodal pore structure was prepared by solvothermal method. The catalyst samples were structurally characterized by N2 adsorption-desorption, XRD, SEM/TEM, and functionally evaluated by temperature programmed reduction (TPR), and temperature programmed desorption of hydrogen (H2-TPD), or carbon dioxide (CO2-TPD). The addition of MgO and La2O3 leads to a better dispersion of Ni on the catalytic surface. Ni/LaSi and Ni/CeSi present a higher proportion of moderate strength basic sites for CO2 activation compared to Ni/Si, while Ni/MgSi lower. CO2 methanation was performed in the temperature range of 150–350 °C and at atmospheric pressure, all silica supported Ni catalysts showing good CO2 conversion and CH4 selectivity. The best catalytic activity was obtained for Ni/LaSi: CO2 conversion of 83% and methane selectivity of 98%, at temperatures as low as 250 °C. The used catalysts preserved the multimodal pore structure with approximately the same pore size for the low and medium mesopores. Except for Ni/CeSi, no particle sintering occurs, and no carbon deposition was observed for any of the tested catalysts.

scholarly journals TiO2 Based Nanostructures for Photocatalytic CO2 Conversion to Valuable Chemicals

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 326 ◽  
Author(s):  
Abdul Razzaq ◽  
Su-Il In
Keyword(s):  
Noble Metals ◽  
Photocatalytic Performance ◽  
Light Trapping ◽  
High Surface ◽  
Three Dimensional ◽  
Value Added ◽  
Co2 Conversion ◽  
Surface Areas ◽  
Tio2 Nanosheets ◽  
Photocatalytic Co2 Conversion

Photocatalytic conversion of CO2 to useful products is an alluring approach for acquiring the two-fold benefits of normalizing excess atmospheric CO2 levels and the production of solar chemicals/fuels. Therefore, photocatalytic materials are continuously being developed with enhanced performance in accordance with their respective domains. In recent years, nanostructured photocatalysts such as one dimensional (1-D), two dimensional (2-D) and three dimensional (3-D)/hierarchical have been a subject of great importance because of their explicit advantages over 0-D photocatalysts, including high surface areas, effective charge separation, directional charge transport, and light trapping/scattering effects. Furthermore, the strategy of doping (metals and non-metals), as well as coupling with a secondary material (noble metals, another semiconductor material, graphene, etc.), of nanostructured photocatalysts has resulted in an amplified photocatalytic performance. In the present review article, various titanium dioxide (TiO2)-based nanostructured photocatalysts are briefly overviewed with respect to their application in photocatalytic CO2 conversion to value-added chemicals. This review primarily focuses on the latest developments in TiO2-based nanostructures, specifically 1-D (TiO2 nanotubes, nanorods, nanowires, nanobelts etc.) and 2-D (TiO2 nanosheets, nanolayers), and the reaction conditions and analysis of key parameters and their role in the up-grading and augmentation of photocatalytic performance. Moreover, TiO2-based 3-D and/or hierarchical nanostructures for CO2 conversions are also briefly scrutinized, as they exhibit excellent performance based on the special nanostructure framework, and can be an exemplary photocatalyst architecture demonstrating an admirable performance in the near future.

Low temperature pseudomorphic synthesis of nanocrystalline carbide aerogels for electrocatalysis

2015 ◽  
Vol 3 (22) ◽  
pp. 11745-11749 ◽  
Author(s):  
Ke Chen ◽  
Xiaowei Huang ◽  
Zhuoxi Zhang ◽  
Ai Du ◽  
Bin Zhou ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Surface ◽  
Surface Areas

Low-temperature pseudomorphic transformation of nanocrystalline TiC (NbC) aerogels with high surface areas and electrocatalytic activities is realized for DSSCs and the HER.

scholarly journals Mn Modified Ni/Bsentonite for CO2 Methanation

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 646 ◽  
Author(s):  
Yuexiu Jiang ◽  
Tongxia Huang ◽  
Lihui Dong ◽  
Tongming Su ◽  
Bin Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Atmospheric Pressure ◽  
Oxygen Vacancies ◽  
Active Component ◽  
Average Pore Size ◽  
Space Velocity ◽  
Co2 Conversion ◽  
Co2 Methanation ◽  
Average Pore ◽  
Gas Space

To enhance the low-temperature catalytic activity and stability of Ni/bentonite catalyst, Ni-Mn/bentonite catalyst was prepared by introducing Mn into Ni/bentonite catalyst and was used for CO2 methanation. The results indicated that the addition of Mn enhanced the interaction between the NiO and the bentonite carrier, increased the dispersion of the active component Ni and decreased the grain size of the active component Ni, increased the specific surface area and pore volume of the Ni/bentonite catalyst, and decreased the average pore size, which suppressed the aggregation of Ni particles grown during the CO2 methanation process. At the same time, the Mn addition increased the amount of oxygen vacancies on the Ni/bentonite catalyst surface, which promoted the activation of CO2 in the methanation reaction, increasing the low-temperature activity and stability of the Ni/bentonite catalyst. Under the reaction condition of atmospheric pressure, 270 °C, V(H2):V(CO2) = 4, and feed gas space velocity of 3600 mL·gcat−1·h−1, the CO2 conversion on the Ni-Mn/bentonite catalyst with 2wt% Mn was 85.2%, and the selectivity of CH4 was 99.8%. On the other hand, when Mn was not added, the CO2 conversion reached 84.7% and the reaction temperature only raised to 300 °C. During a 150-h stability test, the CO2 conversion of Ni-2wt%Mn/bentonite catalyst decreased by 2.2%, while the CO2 conversion of the Ni/bentonite catalyst decreased by 6.4%.

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