Robust mesoporous bimetallic yolk–shell catalysts for chemical CO2 upgrading via dry reforming of methane (original) (raw)
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Advantages of Yolk Shell Catalysts for the DRM: A Comparison of Ni/ZnO@SiO2 vs. Ni/CeO2 and Ni/Al2O3
Chemistry
Encapsulation of metal nanoparticles is a leading technique used to inhibit the main deactivation mechanisms in dry reforming of methane reaction (DRM): Carbon formation and Sintering. Ni catalysts (15%) supported on alumina (Al2O3) and ceria (CeO2) have shown they are no exception to this analysis. The alumina supported catalysts experienced graphitic carbonaceous deposits, whilst the ceria showed considerable sintering over 15 h of DRM reaction. The effect of encapsulation compared to that of the performance of uncoated catalysts for DRM reaction has been examined at different temperatures, before conducting longer stability tests. The encapsulation of Ni/ZnO cores in silica (SiO2) leads to advantageous conversion of both CO2 and CH4 at high temperatures compared to its uncoated alternatives. This work showcases the significance of the encapsulation process and its overall effects on the catalytic performance in chemical CO2 recycling via DRM.
Chemeca 2013, 2013
The activity of Ni supported on mesoporous SBA-15, MCM-41, KIT-6, and a sol-gel prepared Ni/γ γ γ γ-Al 2 O 3, for catalysing methane dry reforming was investigated. The chemical and physical characteristics of the catalysts before and after catalytic testing were investigated using X-Ray diffraction, X-ray Photoemission Spectroscopy, Transmission Electron Microscopy, Scanning Electron Microscopy / Energy Dispersive X-ray analysis, Thermogravimeteric Analysis, Temperature Programmed Reduction techniques and N 2 adsorptiondesorption isotherms. Support type was found to have a significant influence on catalytic activity and stability. Among all the supported catalysts tested, the Ni/SBA-15 exhibited excellent catalytic performance in terms of conversion and long-term stability. The activity for the silica framework catalysts correlated strongly with the surface area and pore diameter of these materials with the degree of CH 4 and CO 2 conversions observed increasing with decreasing surface area and increasing pore diameter.
The activity of Ni supported on mesoporous SBA-15, MCM-41, KIT-6, and a sol-gel prepared Ni/γ γ γ γ-Al 2 O 3, for catalysing methane dry reforming was investigated. The chemical and physical characteristics of the catalysts before and after catalytic testing were investigated using X-Ray diffraction, X-ray Photoemission Spectroscopy, Transmission Electron Microscopy, Scanning Electron Microscopy / Energy Dispersive X-ray analysis, Thermogravimeteric Analysis, Temperature Programmed Reduction techniques and N 2 adsorptiondesorption isotherms. Support type was found to have a significant influence on catalytic activity and stability. Among all the supported catalysts tested, the Ni/SBA-15 exhibited excellent catalytic performance in terms of conversion and long-term stability. The activity for the silica framework catalysts correlated strongly with the surface area and pore diameter of these materials with the degree of CH 4 and CO 2 conversions observed increasing with decreasing surface area and increasing pore diameter.
Jurnal Teknologi, 2016
A series of Ni incorporated Mesostructured Silica Nanoparticles (MSN) were prepared by physical mixing method. Electrolyzed nickel oxide was used as the Ni precursor. The N2 adsorption-desorption and X-Ray diffraction (XRD) analyses evidenced that the increase in Ni loading decreased the surface area and crystallinity, and increased Ni particle size in the catalyst, respectively. The activity of CO2 reforming of CH4 followed the order of 10Ni/MSN > 15Ni/MSN > 5Ni/MSN > MSN. The highest activity was achieved by 10Ni/MSN with the CH4 and CO2 conversion of 63.4% and 87.2 %, respectively. The results indicated that the presence of a suitable Ni amount in MSN was beneficial to achieve high catalytic activity due to its effect on the amount of active metal sites available for the reaction. Thus, the electrolyzed nickel oxide precursor and Ni/MSN catalyst prepared by electrochemical method and physical mixing synthesis has a potential to be utilized in CO2 reforming of CH4.
Nanoscale, 2018
A synergistic approach was made to develop a highly stable and carbon resistant catalyst system based on cobalt and nickel supported over modified mesoporous silica for the dry reforming of methane (DRM). Modified mesoporous silica is prepared by a hydrothermal method, and the total Co & Ni composition is taken at around 5% by using the deposition-precipitation technique. CO2 reforming with methane was performed at 400-800 °C under atmospheric pressure as well as at a pressure of 1 MPa, keeping the CH4/CO2 ratio equal to unity. The catalyst assembly before and after the reaction was thoroughly characterized by a wide range of analytical techniques including N2 physisorption, XRD, TPR, TPO, TPH, XPS, SEM, TEM, elemental mapping, TG-DTG. The physicochemical characterization results confirmed the homogeneous distribution of nanosized metal particles into the hexagonal framework of modified silica, which plays a vital role towards a stronger metal support interaction that renders carbon...
The activity of Ni supported on mesoporous SBA-15, MCM-41, KIT-6, and a sol-gel prepared Ni/-Al 2 O 3, for catalysing methane dry reforming was investigated. The chemical and physical characteristics of the catalysts before and after catalytic testing were investigated using X-Ray diffraction, X-ray Photoemission Spectroscopy, Transmission Electron Microscopy, Scanning Electron Microscopy / Energy Dispersive X-ray analysis, Thermogravimeteric Analysis, Temperature Programmed Reduction techniques and N 2 adsorptiondesorption isotherms. Support type was found to have a significant influence on catalytic activity and stability. Among all the supported catalysts tested, the Ni/SBA-15 exhibited excellent catalytic performance in terms of conversion and long-term stability. The activity for the silica framework catalysts correlated strongly with the surface area and pore diameter of these materials with the degree of CH 4 and CO 2 conversions observed increasing with decreasing surface area and increasing pore diameter.
A short review on mesoporous silica-supported catalysts for methane dry reforming
The National Conference for Postgraduate Research 2016, Universiti Malaysia Pahang, 2016
my (D.-V. N. Vo). Abstract-The aim of this review is to gain a better insight in to the recent developments made in mesoporous silica molecular sieves, such as MCM-41, SBA-15, and SBA-16, as supports for dry reforming of methane. It further explored how different constraints such as the synthesis method for the mesoporous materials and techniques for metal loading on the mesoporous materials influence the dry reforming reactions and products yields. The high surface area and 2D hexagonal arrays of MCM-41 and SBA-15, 3D cage like structure of SBA-16 allow for good dispersion of metals inside their channels, which in turn, facilitates high catalytic activity and less catalyst deactivation. In this review, attention will be given to different strategies for enhancing catalytic activities, and the effect of metal dispersion on mesoporous silica supports.
International Journal of Hydrogen Energy, 2019
In this paper, the effect of pre-treatment and calcination temperature on a series of 5%Co/Al2O3-ZrO2, 5%Ni/Al2O3-ZrO2 and 2.5%Co-2.5%Ni/Al2O3-ZrO2 catalysts for dry reforming of methane was investigated. Main focus of our research was to improve the catalyst stability by proper pre-treatment and reaction conditions. The first approach aimed at the catalyst pre-treatment by using bimetallic systems and the second strategy at the in situ suppression of coke. The catalytic activity of bimetallic system was indeed higher compared to the monometallic in the temperature range of 500-800 °C (space velocity 18000 ml•h-1 •gcat-1 , CH4/CO2 = 1). The bimetallic catalyst calcined at 800 °C showed highest CH4 conversion without deactivation and gave a H2/CO ratio of 91% and 0.96, respectively, and good stability with less coke deposition over 28 h at 800 °C reaction temperature. This improvement is assigned to the synergism between Co and Ni, their high dispersion according to interaction with support. It has been shown in our work that pretreatment temperatures and atmospheres have strong impact on stability of the catalyst. TEM, XRD and TPO investigations confirmed that the slight catalyst deactivation was related to the formation of multiwall carbon nanotubes with hollow inner tube structure. The addition of small amounts of steam or oxygen during DRM improved both the catalyst activity and stability as the bimetallic catalyst lost around 9.4% conversion in DRM, 5.4% in presence of water and only 3.2% in presence of O2.
International Journal of Hydrogen Energy, 2020
In this study, a new nano-sized mesoporous silica (MSN) as support for Ni-based catalysts was produced from natural resources and tested in the dry reforming of methane between 823 and 1023 K. The fresh and spent catalysts Ni-x/MSN (x ¼ 5, 10 and 20 wt.%) were characterized by various techniques. All catalysts are selective for hydrogen production and exhibited long-term stability with low coke formation predominantly as carbon nanotubes, for Ni loadings less than 10% at 973 K. The catalytic results were correlated with the in situ generation of Ni nanoparticles which are highly dispersed on the MSN surface due to strong metal-support interactions thus preventing the sintering process. No significant deactivation was recorded along 25 h on stream meaning that the textural properties of the catalysts have not been altered by the coke deposition or reaction temperature. The prepared MSN is a potential support to be utilized for hydrogen generation.