Browsing by Author "Prof. Dr. M. Asif"

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Fabrication of FeMoWO2/rGO Electrode Materials for High Energy and Power Density for Electrochemical Applications
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Samia Nayab; CIIT/FA23-RPH-036/LHR; Prof. Dr. M. Asif; LHR TP 9862
As increasingly a need to have better, trustworthy and environment-friendly energy storage systems, scholars are working on the development of superiorly advanced electrode materials that can make available both the high energy density and power density. The piece of work involves the synthesis of a novel nanocomposite material comprising reduced graphene oxide (rGO) in combination with iron (Fe), molybdenum (Mo), and tungsten (W) oxides. The FeMoWO 2 /rGO composite has the advantage of both the high redox activity of metal oxides and good conductivity and a high surface area of rGO. They combine to form a material favourable to rapid charge transfer and large storage capacity. A simple hydrothermal process was applied to the chemistry of composite synthesis and coupled with heat treatment aided in ensuring a uniform and stable structure. SEM, XRD all those characterization methods proved to define the quality and good formation of the material. The testing done electrochemically revealed that the FeMoWO2/rGO electrode had a high specific capacitance of 632 F/g at the current density of 1 A/g and energy density of 45.3 Wh/kg. It also exhibited a high stability having 92 percent of its performance retained after 5000 charge- discharge cycles. These findings indicate that FeMoWO2 /rGO composite can be an effective material that is to be employed in high performance supercapacitors and other energy storage devices.
Simulation and Synthesis of Aluminum (Al) Substituted Hematite Nanomaterials
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Qaiser Ali; CIIT/FA18-RPH-040/LHR; Prof. Dr. M. Asif; LHR TP 6362
The recent momentum in energy science has streamlined the photoelectrochemical (PEC) cell conversion of solar to electrical energy. There are various advantages to these PEC cells, such as low-cost thin film processing, a decrease in the loss of absorption (due to translucent electrolytes), and a significant improvement in the efficiency of energy transfer. As a photoanode for water-splitting purposes, alpha-hematite has gained significant attention in modules for photoelectrochemicals (PEC). The nanomaterial alpha-hematite (-Fe2O3) is appealing since to the 2.1eV bandgap, which allows it to absorb visible light. Low cost, chemical stability and abundance in nature, and outstanding photoelectrochemical advantages of -Fe2O3 include (PEC) properties for dividing hydrogen and oxygen into water. -Fe2O3, however suffers from low conductivity, sluggish surface kinetics, and low diffusion of the carrier that causes PEC system output degradation. Higher resistivity, sluggish surface kinetics, poor electron mobility, and higher electro-hole combinations are related to the low carrier diffusion of  -hematite. Doping, which shapes the nanocomposite and nanostructure films, can improve all the inconveniences of -Fe2O3, such as low carrier mobility and electronic diffusion properties. In this project, using the hydrothermal method, all nanomaterials were synthesized and analyzed using Scanning Electron Microscopy (SEM), X-ray Diffractometer (XRD) and density functional theory (DFT), respectively. The morphology of the surface is analyzed by SEM. To define the crystalline phase and approximate the crystalline size, the X-Ray diffractometer (XRD) is used. Density-functional theory (DFT) is a tool of computational quantum mechanical modeling used to investigate the electronic structure (or nuclear structure) of many-body structures, especially atoms, molecules, and condensed phases (primarily the ground state). By aluminum (Al) doping or composite forming containing -Fe2O3, the mobility and carrier diffusion properties of -hematite (-Fe2O3) can be changed. By strain integration into the lattice structure, the new composite, Al- -Fe2O3, strengthened the charging transport properties, thus increasing light absorption. Clustering is seen by the rise in Al content in -Fe2O3 due to the denser formation of the ix Al--Fe2O3 particle. The presence of aluminum allows the structural, optical and morphological properties of Al--Fe2O3 to alter rather than the photocatalyst properties of -Fe2O3. The bandgap from 2.1 to 2.4 eV has a marked difference. A rhombohedra structure is seen by the structure of the composite formation Al-  -Fe2O3, owing to a high percentage of Al. The increased hydrogen production of the Al- -Fe2O3 based photocatalyst is clearly differentiated by the photocurrent (35 A/cm2 ). The composition and morphology of the magnetic properties of the synthesized samples is related. We infer that shape anisotropy mediated enhancement of coercivity in hematite nanoplates, while hematite ellipsoid 3D superstructure (nanoparticle clusters) induced multidomain magnetic structure creation and maximal coercivity, revealing its superior structure for enhanced magnetic properties. The synthesized hematite nanoparticle structures have low levels of cytotoxicity on the cell line of human lung fibroblasts (MRC5), indicating a healthy use for practical applications of these nanoparticles.