Current Issue : April-June Volume : 2024 Issue Number : 2 Articles : 5 Articles
The design of economical and robust catalysts is a substantial challenge for the dry reforming of methane (DRM). Monometallic nickel-based catalysts used for DRM reactions had comparable activity to noble metals. However, they turned out to be less stable during the reactions. As a continuation of the interest in synthesizing catalysts for DRM, this paper evaluates the catalytic performance of bimetallic Co–Ni catalysts regarding their synergy effect, with graphene oxide (GO) as support for the first time. The synthesized bimetallic catalysts prepared via the wet-impregnation method were characterized using N2 physisorption analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The catalytic test was performed in a stainless-steel tubular reactor in atmospheric conditions with a reaction temperature of 800 ◦C, time-on-stream (TOS) of 300 min and CH4: CO2 being fed with a ratio of 1:1. The bimetallic 10 wt%Co– 10 wt%Ni/GO and 20 wt%Co–10 wt%Ni/GO catalysts had a similar BET specific surface area in N2 physisorption analysis. The XRD pattern displayed a homogeneous distribution of the Co and Ni on the GO support, which was further validated through SEM–EDX. The conversion of CO2, CH4, and H2 yield decreased with reaction time due to the massive occurrence of side reactions. High conversions for CO2 and CH4 were 94.26% and 95.24%, respectively, attained by the bimetallic 20 wt%Co–10 wt%Ni/GO catalyst after 300 min TOS, meaning it displayed the best performance in terms of activity among all the tested catalysts....
Ceramic membranes prepared with flat sheet configuration using local materials, iron ore and bentonite, are reported in this investigation. The feedstocks used were fully characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and laser diffraction/light scattering. In order to optimize the preparation conditions, the effect of sintering temperature on the microstructure of ferric and clayey membranes was assessed. Results obtained with SEM, confirmed by optical microscopy, indicate that the optimized sintering temperature was in the vicinity of 900 ◦C. The properties of the fabricated membranes were characterized in terms of mass and thickness loss throughout a determined period of time. The experimental results present a negligible variation in the rate of mass change, which suggested the stability of the synthesized membranes. Both the ferric and clayey membranes exhibit a prevalence of mesopores in their pore distribution. These results suggest that these specific membranes could be employed as cost-effective and environmentally friendly materials. Furthermore, they hold promise for potential applications in gas treatment processes....
This work focuses on the synthesis of silver nanoparticles using fresh cocoa pods from the “Theobroma cacao” extract plant through the reduction of silver ions (Ag+) into Ag (0) by a green chemistry process, subsequently used as an electrode material. Reaction factors such as pH, incubation time, and silver ion concentration were optimized during the formation of nanoparticles. The synthesized nanoparticles were characterized by ultraviolet spectrophotometry (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDX) analysis. Once drop coating was applied on the glassy carbon electrode (GCE), the resulting film was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that silver nanoparticles have been well synthesized and can find applications as electrode materials for simultaneous determination of ascorbic acid and uric acid in aqueous solution....
Photocatalytic nitrogen fixation has attracted much attention because of its ability to synthesize ammonia under mild conditions. However, the ammonia yield is still greatly limited by the sluggish charge separation and extremely highN2 dissociation energy. Herein, two-dimensional Ti3C2 MXene ultrathin nanosheets were introduced to construct Ti3C2/TiO2 composites via electrostatic adsorption for photocatalytic nitrogen fixation. The photocatalytic activity experiments showed that after adding 0.1 wt% Ti3C2, the ammonia yield of the Ti3C2/TiO2 composite reached 67.9 μmol L−1 after 120 min of light irradiation, nearly 3 times higher than that of the monomer TiO2. XPS, DRS, LSV, and FTIR were used to explore the possible photocatalytic nitrogen fixation mechanism. Studies showed that a close interfacial contact has been formed via the bonding mode of =C-O between the Ti3C2 and TiO2 samples. The formed =C-O bond boosts an oriented photogenerated charge separation and transfer in the Ti3C2/TiO2 composite. This work provides a promising idea for constructing other efficient MXene-based composite photocatalysts for artificial photosynthesis....
Sodium-based bentonite is used for drilling operations because of its high swelling capacity. This type of bentonite clay is not sourced locally in many oil- and gas-producing nations. However, low-swelling clays (calcium- and potassium-based) are in abundant quantities in most of these countries. Hence, there is a need to convert low-swelling bentonite clays to sodium-based bentonite. The method used to convert low-swelling clays is more applicable to calcium-based bentonite. This research investigated a thermochemical treatment method that converted potassium-based bentonite to sodium-based bentonite. The raw clay materials were sourced from Pindinga (P) and Ubakala (U) clay deposits in Nigeria. An X-ray diffractometer (XRD), an energy dispersive X-ray (EDX), and a scanning electron microscope (SEM) were used to characterize the raw clay samples. Mud slurry was prepared by mixing 22 g of the local raw clays, 3 wt.% soda ash, and MgO at concentrations between 1 and 3 wt.% and heating at 90 ◦C. The result showed that the viscosities of samples P and U increased from 6 to 26 and 8 to 35.5 cP before and after thermochemical treatment, respectively. Also, due to the thermochemical treatment, the samples’ yield point, consistency factor, consistency index, and thixotropy behavior were all significantly improved....
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