Ahmed Sadeq Al-Fatesh

Effects of Selected Promoters on Ni/Y-Al2O3 Catalyst Performance in Methane Dry Reforming

The Ni catalysts supported on γ-Al2O3 were synthesized by an impregnation method. Their catalytic performance in methane dry reforming was investigated. The reforming reactions were carried out in a microreactor using a CO2:CH4 feed ratio of 1:1, a F/W = 2640 ml/(h·g), reaction temperatures between 500-850 (C, and at atmospheric pressure. The influence of Ca, Ce, and Zr promoters on catalyst stability, coke deposition, and the H2/CO ratio were also studied. Effluents were analyzed using an online gas chromatograph equipped with a thermal conductivity detector. The spent and fresh catalysts were characterized by scanning electron microscopy and thermogravimetric analysis. It was found that 3%Ni/γ-Al2O3 promoted with 0.15% Ce and 0.05% Ca gave the best performance and resulted in less coke formation. The highest CH4 and CO2 conversion activities were found to be 94.1% and 98.3% at 850 (C, respectively. Stability tests were carried out for 130 h and this provided a H2 yield of 91%. Moreover, the amount of formed carbon was negligible and did not increase to more than 1.5 wt%.

Role of La2O3 as Promoter and Support in Ni/γ-Al2O3 Catalysts for Dry Reforming of Methane

Abstract The nature of support and type of active metal affect catalytic performance. In this work, the effect of using La2O3 as promoter and support for Ni/γ-Al2O3 catalysts in dry reforming of methane was investigated. The reforming reactions were carried out at atmospheric pressure in the temperature range of 500–700 °C. The activity and stability of the catalyst, carbon formation, and syngas (H2/CO) ratio were determined. Various techniques were applied for characterization of both fresh and used catalysts. Addition of La2O3 to the catalyst matrix improved the dispersion of Ni and adsorption of CO2, thus its activity and stability enhanced.

Stabilities of zeolite-supported Ni catalysts for dry reforming of methane

Ni/γ-Al2O3, Ni/Y-zeolite, and Ni/H-ZSM-5 catalysts were prepared using the incipient wetness impregnation method. Their catalytic performance in dry reforming of methane was studied. The fresh and used catalysts and deposited carbon were characterized using H2 temperature-programmed reduction, temperature-programmed oxidation, N2 adsorption-desorption, X-ray diffraction, and thermogravimetric analysis. The H-ZSM-5-supported Ni catalyst proved to be more stable than the other two catalysts, as it had the lowest carbon deposition.

Investigation of Suitable Pretreatment for Dry Reforming of Methane Over Ni/Al2O3

Carbon dioxide reforming of methane to synthesis gas over an alumina-supported 1% Ni-based catalyst was investigated at atmospheric pressure. The effects of activation and calcination temperatures and the addition of calcium promoted on dry reforming catalysts supported on low surface area alumina Ni/α-Al2O3 (SA-5239) were studied experimentally. In this study, the prepared catalyst was tested in a micro tubular reactor at temperature ranges of 500, 600, 700 and 800°C, atmospheric pressure, using a total flow rate of 33 ml/min. of feed gas 3 ml/min of N2, 15 ml/min of CO2 and 15 ml/min of CH4. The calcination was carried out in the range of 500-900°C. The catalysts were activated inside the reactor at 500-800°C using hydrogen gas. It was observed that calcination enhances catalyst activity which increases as calcination and reaction temperatures were increased. It was found essential activating reforming catalysts with H2.The highest process activity was obtained at 800°C reaction temperature by using catalyst calcined and activated at 900°C and 700°C respectively. The addition of Ca promoter decreases the coke formation on catalyst, however, It initially reduces the activity. The catalyst characterization conducted supported the observed experimental result

Hydrogen production by catalytic methane decomposition over Ni, Co, and Ni-Co/Al2O3 catalyst

ABSTRACT Hydrogen is a chief source of energy. Catalytic decomposition produces hydrogen and carbon. In this work, x%M/Al2O3 (where M is Ni, Co and combined Ni-Co, and x is 10%, 15%, and 30%) has been successfully employed as a catalyst. The effect of activation temperature and active metal type and loading on catalyst perfomance was investigated. The catalysts were characterized with BET, XRD, TPO, TPR, TEM, XPS, and Raman. The results displayed that the 30%Co/Al2O3 catalyst activated at 500°C provided the greatest catalytic performance toward methane conversion. 30%Co/Al2O3 catalyst activated at 500°C formed amorphous carbon.

Synthesis of chitosan based semi-IPN hydrogels using epichlorohydrine as crosslinker to study the adsorption kinetics of Rhodamine B

AbstractThe present study is focused on the preparation of chitosan (CS)/polyacrylonitrile (PAN) blend and semi-interpenetrating polymer network (sIPN) hydrogel films, and their application to the adsorption of Rhodamine B dye. The CS/PAN blend hydrogel films were prepared by solution casting technique. To prepare sIPN, CS was cross-linked with epichlorohydrin (ECH). The developed CS/PAN blends and sIPN hydrogels were characterized with field emission scanning electron microscope (FESEM) and Fourier transform infrared (FT-IR) spectroscope. The FESEM micrographs showed no phase separation between CS and PAN. The cross-linking of CS in the sIPN was confirmed by FT-IR. The degree of swelling, WUB water content, and aqueous stabilities of the blends and sIPN hydrogels were examined at room temperature. Blend film (C8/P2) showed highest % degree of swelling (~2,400%), increased % unbound water (WUB) (52%), and fair degree of aqueous stability. The swelling of the blends decreased not only with an increase in P...

Methane decomposition over Fe supported catalysts for hydrogen and nano carbon yield

Abstract Production of hydrogen, being an environmentally friendly energy source, has gained a lot of attention in the recent years. In this article, iron-based catalysts, with different active metal loadings, supported over magnesia and titania are investigated for hydrogen production via catalytic decomposition of methane. The catalytic activity and stability results revealed that magnesia supported catalysts performed better than titania supported catalysts. Hydrogen reduction temperature of 500°C was obtained suitable for catalyst activation. For magnesia supported catalysts, only higher loadings i.e., 30% and 40% Fe-Mg catalysts showed reasonable activity, while all titania supported catalysts presented less activity as well as deactivation. Among all the catalysts, 30% Fe/MgO catalyst displayed better activity. The formation of carbon nanofibers was evidenced from morphological analysis. FESEM and TEM images showed the generation of nonuniform carbon nanofibers with broader diameter. The catalysts were characterized using different techniques such as BET, H2-TPR, O2-TPO, XRD, TGA, FESEM and TEM.

Reforming of Methane by CO2 over Bimetallic Ni-Mn/γ-Al2O3 Catalyst

γ-Al2O3 supported Ni-Mn bimetallic catalysts for CO2 reforming of methane were prepared by impregnation method. The reforming reactions were conducted at 500–700 °C and atmospheric pressure using CO2/CH4/N2 with feed ratio of 17/17/2, at total flow rate of 36 mL/min. The catalytic performance was assessed through CH4 and CO2 conversions, synthesis gas ratio (H2/CO) and long term stability. Catalytic activity and stability tests revealed that addition of Mn improved catalytic performance and led to higher stability of bimetallic catalysts which presented better coke suppression than monometallic catalyst. In this work, the optimum loading of Mn which exhibited the most stable performance and least coke deposition was 0.5wt%. The fresh and spent catalysts were characterized by various techniques such as Brunauer-Emmett-Teller, the temperature programmed desorption CO2-TPD, thermogravimetric analysis, X-ray diffraction, scanning electron microscope, EDX, and infrared spectroscopy.

Template-free synthesis of nitrogen doped carbon materials from an organic ionic dye (murexide) for supercapacitor application

The present study describes a template-free single step carbonization route to prepare hierarchically structured nitrogen-doped carbon materials (NCMs) by using an organic ionic dye (OID), ammonium purpurate (murexide). These NCMs exhibited moderate specific surface area (307 m2 g−1 for NCM(MDE)-900) and hierarchical macro/meso/microporous structures with abundant nitrogenous functionalities that contributed towards the high specific capacitance displayed by pseudocapacitive contribution. In particular, the NCM(MDE)-800 displayed superior specific capacitance (222 F g−1 at 3 A g−1) and excellent cyclic stability of ∼10 000 cycles at 10 A g−1 in 1 M 1.0 M H2SO4(aq). The material prepared at higher temperature, viz. NCM(MDE)-900, exhibited high rate capability at 50 A g−1, which is 92% of their specific capacitances at 10 A g−1. Further systematic investigations of NCM(MDE)-800 in three different electrolytes, viz. 1.0 M H2SO4(aq), 6 M KOH(aq) and 0.5 M Na2SO4(aq), revealed that 1.0 M H2SO4(aq) is a promising electrolyte for achieving good specific capacitance, high capacitive retention and long term cyclic stability, which might have its origins in the formation of ionic interactions between the active protons in 1.0 M H2SO4(aq) and the alpha carbon atoms with Lewis basic character next to the nitrogen in these NCMs.

Effect of Calcium Promoter on Ni-Based Catalysts Supported on α-Al2O3 and TiO2-P25

CH4 and CO2 are greenhouse gases. Hence, their emission to the atmosphere must be controlled to avoid the global warming. Dry reforming of methane could provide a valuable tool in alleviating this problem as well as producing synthesis gas. This process is hampered by rapid catalyst deactivation due to carbon deposition and sintering of both the support and active metal. The presented study focuses on the experimental investigation the effect of addition of Calcium promoter to 1%Ni catalysts supported on a mixed 80%α-Al2O3 and 20%TiO2-P25 support. The performance of the developed catalyst was quantified by determining CH4 and CO2 conversions, synthesis gas ratio (H2/CO) and stability. Spent and fresh catalysts were characterized by TGA, SEM and EDS. Time on stream stability tests of the promoted catalyst showed that addition of limited amounts of Ca promoter would reduce carbon formation.