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.

Pt/UiO-66 Nanocomposites as Catalysts for CO2 Methanation Process

2019 ◽  
Vol 19 (6) ◽  
pp. 3187-3196 ◽  
Author(s):  
Maria Mihet ◽  
Gabriela Blanita ◽  
Monica Dan ◽  
Lucian Barbu-Tudoran ◽  
Mihaela D Lazar
Keyword(s):  
Thermal Stability ◽  
Surface Area ◽  
Metal Organic Framework ◽  
Catalytic Performance ◽  
Molar Ratio ◽  
High Dispersion ◽  
Co2 Methanation ◽  
Preparation Methods ◽  
Good Thermal Stability ◽  
Catalytic Support

Pt/UiO-66 nanocomposites with platinum target concentration of 3 wt.% were prepared by 3 preparation methods, characterized and tested in the CO2 methanation process. Choice of the microporous UiO-66 metal-organic framework (Zr6O4(OH)4 with 1,4-benzene-dicarboxylate ligand) as catalytic support was motivated by the CO2 chemisorption capacity (proven by CO2-TPD profiles), large specific surface area (1477 m2/g) which favors a high dispersion of metal nanoparticles and good thermal stability. The preparation methods for the Pt/UiO-66 nanocomposites are: (1) wetimpregnation followed by reduction in H2 at 200 °C for 2 h; (2) wet-impregnation followed by reduction with an aqueous solution of NaBH4; and (3) “double-solvent” method, followed by reduction with NaBH4. The UiO-66 based nanocomposites were characterized by N2 adsorption–desorption (BET method), XRD, and SEM/TEM. The Pt/UiO-66 catalyst prepared by method 3 was chosen for catalytic testing due to its highest surface area, smallest platinum nanoparticles (PtNPs) size, the localization of PtNPs both on the grain’s internal and external surface and best thermal stability in the desired temperature range. Its capacity to adsorb and activate CO2 and H2 was evaluated in thermo-programmed desorption experiments (H2-TPD and CO2-TPD). Hydrogen is molecularly adsorbed, while CO2 is adsorbed both molecularly and dissociatively. The catalytic performance in the CO2 methanation process was evaluated by Temperature Programmed Reactions (TPRea, 2 °C/min, 30–350 °C), at atmospheric pressure. The best results were obtained at 350 °C, CO2:H2 molar ratio of 1:5.2 and GHSV ═ 1650 h−1. In these conditions CO2 conversion is almost 50% and CH4 selectivity is 36%, the rest of the converted CO2 being transformed in CO.

scholarly journals Comparison in thermal stability and catalytic performance of H4PMo11VO40 heteropolyacid supported on mesoporous and macroporous silica materials

2020 ◽  
pp. 174751982092599
Author(s):  
Heng Zhang ◽  
Chunhao Yang ◽  
Shengying Zhao ◽  
Tingting Wang ◽  
Wancheng Zhu
Keyword(s):  
Thermal Stability ◽  
Active Sites ◽  
Catalytic Performance ◽  
High Dispersion ◽  
High Exposure ◽  
Macroporous Silica ◽  
One Dimensional ◽  
Ordered Macroporous ◽  
The One ◽  
Mcm 41

Ordered mesoporous silica, SBA-15 and MCM-41, and three-dimensionally ordered macroporous SiO2 were used as the supports of H4PMo11VO40 heteropolyacid for methacrolein oxidation. The dispersion and structural evolutions of the heteropolyacid along with thermal treatment were investigated. It was found that the heteropolyacid entered the one-dimensional mesoporous channels of SBA-15 and MCM-41, and the crystallization and growth were limited, leading to high dispersion of the heteropolyacid. However, the thermal stability was decreased under high dispersion. The migration of the heteropolyacid was observed to the end of the one-dimensional channels of SBA-15 and the outer surface of MCM-41 with calcination, accompanied by the decomposition of the heteropolyacid and the formation of MoO3. In comparison, the crystallization and growth of heteropolyacid were not limited in the open macropores of three-dimensionally ordered macroporous SiO2. Dispersed particles on the surface of the macropores with size of about 5 nm exhibited a higher thermal stability. The decomposition of the heteropolyacid in the SBA-15 and MCM-41 supported catalysts resulted in the loss of strong acid sites, causing low selectivity to methacrylic acid in methacrolein oxidation. High thermal stability with high exposure of the active sites in the three-dimensionally ordered macroporous SiO2 supported catalyst contributed to the enhancement in the catalytic performance.

Recoverable Microparticle-Supported Metal Nanocatalysts

2019 ◽  
Author(s):  
Arthur Bonfá Fernandes ◽  
Mariia V. Pavliuk ◽  
Cristina Paun ◽  
Alexandrina C. Carvalho ◽  
Cassiana S. Nomura ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Metal Oxide Nanoparticles ◽  
Catalytic Performance ◽  
Chemical Transformations ◽  
Flow Conditions ◽  
Facile Synthesis ◽  
Mild Conditions ◽  
One Step ◽  
The One ◽  
Supported Metal

Metal nanoparticles have been widely exploited in catalysis, but their full impact on the environment and human health is still under debate. Here we describe the one-step fabrication of polymer microbead-supported metal and metal oxide nanoparticles and their application as recoverable nanocatalysts for reactions under batch and flow conditions. Au, Ag and Fe<sub>3</sub>O<sub>4</sub> nanoparticles were prepared directly at the surface of benzylamine-coated spherical polymer beads in water by using low energy microwave radiation. The morphology and size of the nanoparticles, and therefore their catalytic properties, were tuned by modifying the bead surface using betalamic acid, an antioxidant from plant origin. The catalytic performance and recovery of these environmentally friendly nanocatalysts was demonstrated towards model redox chemical transformations. We anticipate the results reported herein can provide important insights into the controlled and facile synthesis of microparticle supported nanocatalysts under mild conditions.

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.

One-Step FSP Synthesis of Nanocrystalline Fe/Al2O3 and Fe-Ce/Al2O3 Catalyst for CO2 Hydrogenation Reaction

2018 ◽  
Vol 916 ◽  
pp. 134-138 ◽  
Author(s):  
Kanyarat Piriyasurawong ◽  
Sunthon Piticharoenphun ◽  
Okorn Mekasuwandumrong
Keyword(s):  
Catalytic Activity ◽  
Iron Oxide ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
Flame Spray ◽  
One Step ◽  
Temperature Programmed ◽  
The One ◽  
Long Chain ◽  
Chain Hydrocarbon

Nanocrystalline Fe/Al2O3and Fe-Ce/Al2O3catalysts doped with various amounts of cerium were prepared using the one-step flame spray pyrolysis (FSP) technique. The characterization of the catalysts was measured by several methods such as X-ray diffraction, nitrogen physisorption and hydrogen temperature programmed reduction (H2-TPR) techniques. The results revealed that the FSP-made catalyst exhibited the characteristic pattern of FeAl2O4phase without any phases of aluminum or iron oxide. In addition, cerium (Ce) dopant did not alter crystal structure at low content. However, 7 wt% content of cerium dopant resulted in the formation of ceria (CeO) and iron oxide (Fe2O3) phase. The catalytic performance of the FSP-made catalyst was tested in carbon dioxide hydrogenation for selective production of long chain hydrocarbon, and was compared to conventional impregnation-made catalysts. In the comparison, the FSP-made catalyst exhibited lower catalytic activity but possessed a higher long chain hydrocarbon selectivity. After doping with Ce, the catalytic activity was improved while the hydrocarbon selectivity was decreased and shifted to the short chain hydrocarbon product. In the case of conventional-made catalysts, the activity remained unchanged but the hydrocarbon selectivity was decreased. Among all catalysts, the FSP-made Fe-Ce/Al2O3catalyst with 3% Ce-promoted catalyst exhibited the best performance in terms of selectivity to long chain hydrocarbon.

scholarly journals Reaction mechanisms and catalysis in the one-step synthesis of methylal via methanol oxidation

2021 ◽  
Author(s):  
Meng Yuan ◽  
Mengru Dong ◽  
Zhiwei Tian ◽  
Yuanjun Che ◽  
Yuanyu Tian ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Methanol Oxidation ◽  
Reaction Mechanisms ◽  
Circulating Fluidized Bed ◽  
Product Distribution ◽  
Catalytic Performance ◽  
Pilot Scale ◽  
Methanol Production ◽  
One Step ◽  
The One

This paper reports on the scaling-up of a one-step methanol production process from the laboratory scale to the pilot scale. This lays the foundation for the industrialization of a one-step process for preparing DMM from methanol. After a long period of operation in the circulating fluidized bed, the Fe-Mo/HZSM-5 catalyst was shown to have high stability and carbon deposition resistance, and the regeneration effect of the circulating regeneration fluidized bed was better. In addition, in-situ DRIFTS was used to explore the effects of reaction time, the Mo-Fe ratio and carrier Si-Al ratio on the reaction and product distribution. It was found that the synergistic effect of oxidation centers and acid centers was the fundamental reason for the excellent catalytic performance of the Fe-Mo/HZSM-5 catalyst. And proposed the reaction mechanisms in the one-step synthesis of methylal via methanol oxidation.

Catalytic performance of Cu–Mg–Al in the one-step synthesis of 2-ethylhexanol from n-butyraldehyde

2018 ◽  
Vol 125 (2) ◽  
pp. 773-788 ◽  
Author(s):  
Shuang Miao ◽  
Hualiang An ◽  
Xinqiang Zhao ◽  
Yanji Wang
Keyword(s):  
Catalytic Performance ◽  
One Step ◽  
The One

scholarly journals CO2 Methanation over Hydrotalcite-Derived Nickel/Ruthenium and Supported Ruthenium Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1008 ◽  
Author(s):  
Joana A. Martins ◽  
A. Catarina Faria ◽  
Miguel A. Soria ◽  
Carlos V. Miguel ◽  
Alírio E. Rodrigues ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Ruthenium Catalysts ◽  
Emission Spectrometry ◽  
Co2 Conversion ◽  
Co2 Methanation ◽  
Inductively Coupled ◽  
Weight Hourly Space Velocity

In this work, in-house synthesized NiMgAl, Ru/NiMgAl, and Ru/SiO2 catalysts and a commercial ruthenium-containing material (Ru/Al2O3com.) were tested for CO2 methanation at 250, 300, and 350 °C (weight hourly space velocity, WHSV, of 2400 mLN,CO2·g−1·h−1). Materials were compared in terms of CO2 conversion and CH4 selectivity. Still, their performances were assessed in a short stability test (24 h) performed at 350 °C. All catalysts were characterized by temperature programmed reduction (TPR), X-ray diffraction (XRD), N2 physisorption at −196 °C, inductively coupled plasma optical emission spectrometry (ICP-OES), and H2/CO chemisorption. The catalysts with the best performance (i.e., the hydrotalcite-derived NiMgAl and Ru/NiMgAl) seem to be quite promising, even when compared with other methanation catalysts reported in the literature. Extended stability experiments (240 h of time-on-stream) were performed only over NiMgAl, which was selected based on catalytic performance and estimated price criteria. This catalyst showed some deactivation under conditions that favor CO formation (high temperature and high WHSV, i.e., 350 °C and 24,000 mLN,CO2·g−1·h−1, respectively), but at 300 °C and low WHSV, excellent activity (ca. 90% of CO2 conversion) and stability, with nearly complete selectivity towards methane, were obtained.

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.

scholarly journals Rapid Aging as a Key to Understand Deactivation of Ni/Al2O3 Catalysts Applied for the CO2 Methanation

2021 ◽  
Author(s):  
Dennis Beierlein ◽  
Dorothea Häussermann ◽  
Yvonne Traa ◽  
Elias Klemm
Keyword(s):  
Catalytic Performance ◽  
Temperature Programmed Reduction ◽  
Co2 Methanation ◽  
X Ray ◽  
Actual Application ◽  
Time Period ◽  
Temperature Programmed ◽  
The One ◽  
Long Term Measurement

Abstract We developed a rapid aging method for Ni/Al2O3 methanation catalysts mimicking the real aging in the actual application. The method is based on hydrothermal deactivation of the catalyst at 600 or 700 °C, which leads to a catalyst with nearly constant conversion after a much shorter time period compared to normal aging. The hydrothermally aged catalysts are characterized by N2 adsorption, X-ray powder diffraction, temperature-programmed reduction and H2 chemisorption. The catalytic performance of the aged catalysts is comparable to the one of a catalyst deactivated in a long-term measurement with up to 720 h on stream. The time needed for reaching a stable conversion can be diminished by rapid aging by a factor of 10. The investigations also showed that the long-term deactivation is caused by Ni particle sintering and that the support pores limit the Ni particle size. Graphical Abstract

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