Department of Physics
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Item Extraction of Activated Carbon from Biomass for Energy Storage Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Farzana Bashir; CIIT/FA20-RPH-045/LHR; Dr. Ishrat Sultana; LHR TP 8001The current energy crisis is at its peak, and traditional energy sources are inadequate to supply modern energy demand. Consequently, the energy storage technology that can sustain current requirements is in high demand. Batteries and supercapacitor are examples of electrochemical energy storage devices (EESDs) that have been developed for a long time as crucial force sources in our daily lives. Orange peel, banana peel, wheat straw, olive stone, pistachio shells, walnut shells, beech wood, and hard coal, among other waste biomass sources, are used to produce activated carbon (AC). Activated carbon is used in energy storage applications due to high electrolyte wettability, high reactivity, and high thermal stability. Non- porous carbons are generated by the environmentally friendly, cheap, and low-temperature method of hydrothermal carbonization. For un-activated carbon we take 20 g of corn hair fiber and make gel in 100 ml DI water material was placed in autoclave at 250 ºC for 16 h. Activated carbon and KOH was taken by the ratio of 1:4 respectively, then grinding it in mortar and pestle, heated at 700-800 ºC at the 3 ºC min-1 ramp in a horizontal furnace under a nitrogen flow environment and held at this temperature for 1h. Hydrothermal process and temperature pyrolysis results in increased content of carbon and its aromatic nature in activated carbon. The percent yield of Activated carbon obtained through this method is much higher than other methods. Raman spectroscopy and Fourier transform infrared spectroscopy were used to evaluate the sample and approximate its composition. Cyclic voltammetry and electrochemical impedance spectroscopy were used to explore the sample's electrochemical properties. CV and Specific capacitance show the enhancement of conductivity. The material has the highest specific capacitance 235 Fg-1.Item Acerbic Fluorescent Spectroscopy of Carbon dots for Biomedical Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) FAZAL UL NISA; CIIT/SP19-RPH-007/LHR; Dr. Naima Amin; LHR TP 6370Carbon nanodots are well known in biomedical aspects due to their novel fluorescent properties. Nitrogen based carbon nanodots has showed the great photoluminescence and increased fluorescence quantum yield. The pH in living cells is very important as a lot of physiological systems are working in our body to keep them within a specific range. A slight change in pH can cause imbalance in cell function and growth. There are many diseases, which are associated with pH change (acidic pH) such as cancer, tuberculosis, and infections. Hence, a sensitive and selective system is needed to monitor the pH in living cells. The composition of carbon nanodots with Polypropylene glycol and 1,4- benzenediamine showed better chemical stability, high biocompatibility, intense photoluminescence. Therefore, they can be used to evaluate pH detection in living cells. The purpose of this study is to produce nitrogen-based carbon nanodots that are susceptible to show photoluminescence properties and high quantum yield. NCDs were synthesized via Microwave assisted method which is a very facile and cost-effective technique. The synthesized carbon nanodots were then characterized by using FT-IR, AFM, UV-Vis and Fluorescence spectroscopy. FT-IR spectra confirmed the presence of carboxyl functional groups on the surface of carbon nanodots. AFM results indicates that the produced carbon nanodots are spherical and have diameter in the range of 1-5 nm. All these experiments confirm that synthesized carbon nanodots possess high photoluminescence, better quantum yield henceforward they can be used for pH detection and other biomedical applicationsItem Extraction of Carbon Based Biochar fromWasted Biomass for Energy Storage Application(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Aftab Javid; CIIT/FA23-RPH-003/LHR; Dr. Muhammad Aamir Razaq; LHT TP 9838The growing need for powerful eco-friendly energy storage has determined research into better electrode materials for supercapacitors. Supercapacitors famous for their fast charge and discharge cycles and high-power output, but their energy storage capacity remains relatively low, when relying on Bismuth Sulfide (Bi₂S₃). To solve this, we use Biochar, a carbon-rich material that can both store more electrons and also facilitates fast electron transport. In this study, we created a binder-free electrode by growing Bi₂S₃ directly onto Biochar made from Amal Tass pods biomass waste, using a fast microwave-assisted process. First, we turned the Amal Tass pods into conductive biochar through drying, grinding, and a simple hydrothermal step. Then mixed this biochar into water with Bi(NO₃)₃·5H₂O and thiourea, and exposed the mixture to microwave energy and a uniform Bi₂S₃–Biochar composite formed, no binders or extra additives needed. This composite delivers a high energy density, making it a strong candidate to replace batteries. Raman spectroscopy confirmed that Bi₂S₃ adopted its orthorhombic crystal structure within the carbon matrix, and it also showed the characteristic D- and G-bands of biochar at 1391 and 1595 cm⁻¹. When we tested the composite in 2 M KOH, cyclic voltammetry revealed clear redox peaks whose areas raised with scan rate, indicating strong pseudocapacitive behavior. Electrochemical impedance spectroscopy showed low charge-transfer resistance, which means ions and electrons move through the material with ease. Together, these results demonstrate that our quick, green microwave method produces Bi₂S₃–Biochar electrodes that combine high power with improved energy storage an encouraging step toward the next generation of sustainable pseudocapacitors.