Sami ullah Rather

Preparation of activated carbon from fly ash and its application for CO2 capture

Power and desalination plants are one of the main anthropogenic sources for CO2 generation, which is one of the key elements to cause greenhouse gas effect and thus contribute to the global warming. Fly ash (FA) generated in desalination and power plants was converted into activated carbon (AC) treated with KOH at higher temperature and tested for CO2 capturing efficiency. Morphological characteristics of FA such as BET specific surface area (SSA), pore volume, pore diameter, and pore size distribution (PSD) were performed using N2 adsorption isotherm. CO2 adsorption capacity and adsorption isotherms of CO2 over AC were measured by performing thermogravimetric analysis at different temperatures. BET SSA of 161 m2g−1 and adsorption capacity of 26mg CO2/g AC can be obtained by activation at KOH/FA ratio of 5 at 700 °C and activation time of 2 h. Therefore, great potential exists for producing AC from FA, which will have the positive effect of reducing the landfill problem and global warming.

Partial oxidation of methanol over Au/CeO2–ZrO2 and Au/CeO2–ZrO2–TiO2 catalysts

Experimental data on hydrogen production via a partial oxidation of methanol (POM) reaction on Au/ZrO2, Au/CeO2–ZrO2 and Au/CeO2–ZrO2–TiO2 catalysts is presented in this article. The gold catalysts were prepared by a deposition–precipitation (DP) method and characterized by XRF, XRD, H2-TPR, XPS methods N2 adsorption. The activity results show that the catalyst containing 1 wt% gold supported on a CeO2–ZrO2 carrier demonstrates very good hydrogen selectivity and the highest catalytic activity among all tested catalysts. The optimal working temperature established was 375 °C. At this temperature 75.5% hydrogen selectivity was registered. The presence of oxidized gold in the catalysts composition as well as the support redox properties are the major factors controlling the observed catalytic activity.

Review of solid state hydrogen storage methods adopting different kinds of novel materials

Overview of advances in the technology of solid state hydrogen storage methods applying different kinds of novel materials is provided. Metallic and intermetallic hydrides, complex chemical hydride, nanostructured carbon materials, metal-doped carbon nanotubes, metal-organic frameworks (MOFs), metal-doped metal organic frameworks, covalent organic frameworks (COFs), and clathrates solid state hydrogen storage techniques are discussed. The studies on their hydrogen storage properties are in progress towards positive direction. Nevertheless, it is believed that these novel materials will offer far-reaching solutions to the onboard hydrogen storage problems in near future. The review begins with the deficiencies of current energy economy and discusses the various aspects of implementation of hydrogen energy based economy.

Nanomaterials for renewable energy storage: synthesis, characterization, and applications

1Department of Chemical and Materials Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia 2Gas Processing Center, College of Engineering, Qatar University, P.O. Box 2713, Doha, Qatar 3Electrochemical Power Systems Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630006, India 4SABIC Chair in Catalysis, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia 5Game Lab, Chenergy Group, Department of Applied Science and Technology (DISAT), Politecnico Di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy

Trimetallic catalyst synthesized multi-walled carbon nanotubes and their application for hydrogen storage

Multi-walled carbon nanotubes (MWCNTs) were synthesized by rapid thermal decomposition method using trimetallic catalyst supported MgO. MWCNTs prepared via trimetallic catalyst shows much higher BET specific surface area compared to current monometallic and bimetallic catalyst. As-grown and pristine MWCNTs were found to adsorb nitrogen reversibly and their adsorption uptake exhibits type-II BET isotherm. Existence of small impurities, such as metal and metal oxides present in the MWCNTs, was confirmed by thermogravimetric analysis as well as via energy-dispersive X-ray spectroscopy. An over 10 wt% enhancement of hydrogen storage capacity of as-grown MWCNTs compared to pristine was found to be due to the presence of impurities. Fast kinetics and complete reversibility gives indication that the process responsible for hydrogen adsorption uptake in MWCNTs is physisorption. A linear relation between hydrogen uptake (~0.22 and 0.20 wt%) and equilibrium hydrogen pressure was obtained for both as-grown and pristine MWCNTs.

Effect of micro- to nanosize inclusions upon the thermal conductivity of powdered composites with high and low interface resistance

Materials for thermal management application require better control over the thermophysical properties, which has largely been achieved by fabricating powdered composite. There are, however, several factors like filler volume fraction, shape morphology, inclusion size, and interfacial thermal resistance that limit the effective properties of the medium. This paper presents a methodology to estimate the effective thermal conductivity of powdered composites where the filler material is more conductive than the matrix. Only a few theoretical models, such as Hasselman and Johnson (HJ) model, include the effect of interfacial resistance in their formulation. Nevertheless, HJ model does not specify the nature of the interfacial thermal resistance. Although Sevostianov and Kachanov (SK) method takes care of interface thickness, they, on the other hand, have not taken into account the interfacial resistance due to atomic imperfections. In the present work, HJ model has been modified using SK method and the results were compared with experimental ones from the literature. It has been found that the effect of interfacial resistance is significant in highly resistive medium at microscale compared to nanoscale, such as Cu/diamond system, while, in a highly conductive medium, like bakelite/graphite system, the effect of shape factor is more significant than interfacial thermal resistance.