Tailored mesoporous silica supports for Ni catalysed hydrogen production from ethanol steam reforming (original) (raw)
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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.
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...
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.
International Journal of Chemical Reactor Engineering, 2007
In the present study, Ni incorporated MCM-41 structured mesoporous catalysts with a Ni/Si atomic ratio of 0.036 and 0.15 were prepared by a direct hydrothermal synthesis procedure. These catalysts had surface area values of 860.5 m2/g (Ni-MCM-41 having a Ni/Si ratio of 0.036) and 944.9 m2/g (Ni-MCM-41 having a Ni/Si ratio of 0.15). They also had narrow pore size distributions with average pore diameters of 2.7-2.6 nm respectively. Ni MCM-41 synthesized by the one-pot hydrothermal synthesis procedure showed very high activity and relatively high hydrogen yield in steam reforming of ethanol in a temperature range between 300-550°C. Besides the steam reforming reaction, formation of some formaldehyde and small amounts of ethylene were also observed at low temperatures for the catalyst containing a Ni/Si ratio of 0.036. The disappearance of formaldehyde and the formation of some methane at high temperatures indicated the increased significance of cracking in addition to reforming and de...
Applied Catalysis B: Environmental, 2011
Steam reforming of ethanol to produce hydrogen was carried out using a two-stage reaction system with several nano-Ni/SiO 2 catalysts prepared at different citric acid (CA) contents using the sol-gel process. The fresh (non-calcined and calcined) catalysts and the reacted catalysts were analysed using surface area and pore size analysis, Fourier-transform infrared (FTIR) spectroscopy, thermo-gravimetry analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that a meso-structured material was produced at Ni:CA ratios lower than 1:0.5; and the pore volume of the catalyst was increased when more citric acid was used during the sol-gel preparation. Gas and hydrogen yield were observed to be increased when the Ni:CA ratio was reduced from 1:0.5 to 1:3.0; however, gas concentration was slightly changed for the catalysts prepared at different Ni:CA ratios. In addition, coke formation was increased from 0.7 to 7.5 wt.% when the Ni:CA ratio decreased from 1:0.5 to 1:3.0. It was also found that the Ni/SiO 2 catalyst prepared at the low CA content (Ni:CA = 0.5) was non-stable during the ethanol steam reforming process; since sintering was obtained as observed using TEM analysis of the used catalyst.
Advanced Materials Research, 2015
We have synthesized mesoporous SiO2 (MCM-41) and TiO2 encapsulated bimetallic Cu-Ni nanocatalysts using an optimized one-pot hydrothermal procedure. The catalysts were characterized using BET, XRD, TGA-DSC and HRTEM techniques. While bimetallic Cu-Ni/MCM-41catalysts have high surface area- 634-1000 m2/g, Cu-Ni/TiO2 yields surface area of 250-350 m2/g depending on the metal loading (5-10 wt%). The XRD studies confirmed a long range ordered structure in Cu-Ni/MCM-41 and the presence of the catalytically active anatase phase in the crystalline Cu-Ni/TiO2. The results from HRTEM studies were consistent with the mesoporosity of both supports. These catalysts were tested for methanol conversion and H2/CO selectivity via steam reforming of methanol (SRM) reactions in a fixed bed reactor. There is a distinct difference in the performance of these two supports. Bimetallic 3.33%Cu6.67%Ni/TiO2 catalyst showed an impressive 99% H2 selectivity at as low as 150°C and a maximum conversion of 92% a...
Chemical Engineering Transactions, 2016
The development of catalysts resistant to deactivation, especially to coke formation, is a key issue to perform ethanol reforming successfully. Aiming at carbon formation minimization, in the present work, bimetallic Pt- Ni/CeO2 catalysts were deposited on silica gel with high surface area and tested for ethanol reforming in the low temperature range (300 - 600 °C). The activity was investigated at different contact times and the impact of oxygen co-feeding on catalyst performances was also studied. The increase of space velocity had no effect on ethanol conversion at T > 420 °C under both oxidative and non-oxidative conditions; however, when O2 was co-fed, contact time growth assured almost total conversion until 300 °C. Moreover, the results of stability tests revealed that O2 addition in the reforming mixture improved catalyst stability, which was maintained for 70 h.