M.Phil / MS
Permanent URI for this collectionhttps://repository.cuilahore.edu.pk/handle/123456789/30
This collection archives the complete set of theses produced by students of the COMSATS University Islamabad, Lahore Campus.
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Item Molybdenum Disulfide-Metal Organic Framework as Electrode Material for Heavy Metal Ions Detection in Aqueous Media(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Fatima Amjad; CIIT/SP24-R06-006/LHR; Dr. Sara Riaz; LHR TP 10017Heavy metal ions (HMIs) are highly hazardous environmental pollutants that pose major threats to aquatic ecosystems and human health due to their non-biodegradable nature and strong tendency to accumulate in living organisms. Therefore, it is essential to develop efficient electrode materials for their electrochemical detection in water. For heavy metal ions detection, a hybrid electrode material based on molybdenum disulfide (MoS₂) and an ytterbium-based metal–organic framework (Yb-MOF) was synthesized and characterized. MoS₂@Yb-MOF composite was developed by synthesizing MoS2 nanosheets and combining them with Yb-MOF to synergistically integrate the active edge sites of MoS2 with high surface area and abundant coordination sites of porous framework of the Yb-MOF. A flexible and conductive electrode was fabricated by directly integrating the composite onto a carbon cloth surface. The successful formation of composite material was confirmed through structural and morphological characterization using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Electrochemical studies conducted using cyclic voltammetry and electrochemical impedance spectroscopy confirmed improved charge transfer behavior and enhanced electrochemical activity of the composite electrode relative to the individual components. These results suggested that the MoS₂@Yb-MOF composite is a promising electrode material for electrochemical detection of heavy metal ions in aqueous media.Item Synthesis of Modified MXene for its Application as Flexible Supercapacitor Electrode Material(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Sidra Mehboob; SP23-R06-020; Dr. Sara Riaz; LHR TP 9467Greenhouse gas emissions and the depletion of finite resources are two major environmental issues brought on by the current reliance on fossil fuels to meet energy demands. Making the switch to renewable energy sources like solar and wind is crucial, but their inconsistent availability calls for efficient storage options. Among these, electrochemical energy storage devices supercapacitors in particular stand out as viable choices because of their long-lasting performance and high power efficiency. As a result, the supercapacitor, an energy storage device, has garnered a lot of attention because of its long lifespan, high cycling stability, environmental safety, and quick charge/discharge rate. In comparison to batteries, supercapacitors have a very high power density. Supercapacitor electrode material is made with higher energy and power density and excellent cyclic stability. In present work, ZIF-8, ZIF-67, MXene, Core shell ZIF-8/ZIF-67 and final composite MXene@ZIF-8/ZIF-67 were synthesized. The final composite was synthesized by self-assembly method with non-covalent interactions. The fabricated material was analyzed by FTIR. Different electrochemical characterizations such as CV, GCD and EIS were performed. The active electrode material was coated on carbon cloth by drop casting method. The potential window is from -0.2 to 1.0 V in 3M sulphuric acid. Composite has specific capacitance 83.3 F/g at 0.5 A/g current density with power and energy density at 0.25 Wkg-1 and 43.3 Whkg-1. This is a good material for enhancing the supercapacitor performance.Item Electrochemical Detection of Heavy Metal Ions Using Graphene/MOF Modified Electrode(Library Information Services COMSATS University Islamabad Lahore Campus, 2021-02-25) Mariam Ghafoor; SP20-R06-009; Dr. Sara Riaz; LHR TP 7564Heavy metals pollution is due to agriculture, mining industry, and industrial activities. Once heavy metal ions pollute environment specially water bodies, they are very difficult to degrade by nature for decades. Over time they accumulate in body and pose serious health problems. Because of these effects, it is necessary to detect heavy metal ions. Therefore, It is essential to design such electrode materials with high porosity and large surface area for their wide range of applicability. Metal Organic Framework have been regarded as the promising electrode materials constituting porous carbon-based electrode materials for electrochemical detection of heavy metal ions. In present work, we fabricated cobalt derived Metal Organic Framework comprising of Zeolitic Imidazolate framework (ZIF-67) and then using ZIF-67 as a precursor for the synthesis of graphene oxide (GO) coated ZIF-67 composite through a facile solvothermal synthesis method. Structural analysis of prepared material was done by using FTIR, Raman analysis and XRD. Electrochemical characterization of our prepared composite electrode material was performed through Electrochemical impedance spectroscopy (EIS) and Cyclic Voltammetry (CV) techniques at potential window of -0.2-0.6 mV/s in 5mM [Fe (CN)6]-3/-4 containing 0.1 M KCl using glassy carbon electrode as a current collector. Differential pulse Voltammetry used for individual detection of toxic heavy metal ions such as Pb, Cr, Hg, and As with lower limit of detection i.e 0.01(μM), 0.12(μM), 0.009(μM), and 0.31(μM) respectively below the permissible limit by WHO. Results revealed that synthesized composite (GO/ZIF-67) electrode material has better electrochemical performance as compared to ZIF-67/GCE, GO/GCE, and bare GCE electrode. Therefore, GO/ZIF-67 composite is determined to have good capability as electrode material in heavy metals detection application due to its porous tunable structural composition.Item Fabrication of a Suitable Visible Light Driven Photocatalyst for Sustainable Production of Hydrogen from Water Splitting(Library Information Services COMSATS University Islamabad Lahore Campus, 2021-02-24) Ayesha Nawaz; FA19-R06-038; Dr. Sara Riaz; LHR TP 7326Excessive use of fossil fuels has caused a lot of environmental damage so they must be replaced with sustainable energy resources. Hydrogen has clean and renewable properties so it can be used as a sustainable energy resource. Photocatalytic water splitting is an efficient way of producing hydrogen but it requires an efficient photocatalyst having high photochemical stability, efficient charge separation capability, good light harvesting properties and suitable band gap. Tungsten oxide has suitable properties for photocatalytic water splitting but it suffers from recombination of photogenerated charge carriers. Herein, different composites of tungsten with transition metal borides and oxides of copper and nickel have been successfully synthesized by precipitation method. FTIR studies, XRD analysis and SEM of the prepared composites, WO3-NiCoB, WO3-CuO-NiO, WO3-NiB and WO3-CuO-NiB have been done for detection of functional group, investigation of crystalline and structural properties, and study of the surface morphology of prepared composites. The photocatalytic activity of WO3, WO3-CuO-NiO and WO3-NiCoB has measured by photodegradation of AO-II. The results of activity showed that WO3-NiCoB worked better in photodegradation of AO-II in comparison to its other counterparts, WO3 and WO3-CuO-NiO.Item A Non-Enzymatic Dopamine Sensor Based on MoS2 Nanosheets Modified Carbon Cloth (CC) Electrode(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-20) Mariam Sabar; SP19-R06-002; Dr. Sara Riaz; LHR TP 6506Dopaminergic neurons are the source of production of neurotransmitter called as dopamine (DA). It serves as chemical carrier in hormonal, renal, cardiovascular and central nervous system. The behavior of brain related with motivation and reward is controlled by dopamine in humans. The irregular level of dopamine results in many neural diseases which includes Alzheimer’s disease, less attention hyperactivity disease, Parkinson’s disease, schizophrenia as well as restless legs syndrome. It also gives information about probability of drug addiction. For that reason, an accurate method for the detection of dopamine is necessary. Here we described a material consisting of molybdenum disulfide nanosheets (MoS2 NSs) which were deposited on a Carbon Cloth (CC) electrode that is well adapted for sensitive and selective detection of level of dopamine. The molybdenum nanosheets deposited on CC was made by hydrothermal method. The composite was characterized with various characterization techniques like Scanning electron microscope (SEM), Cyclic Voltammetry, Fourier transform infrared spectroscopy (FTIR), Amperometric i-t method and electrochemical impedance spectroscopy. The composite represents excellent electrochemical properties like more electrochemically active surface, large capacitance current, more conductivity and more porosity as shown by different electrochemical studies. The carbon cloth electrode shows good electrocatalytic ability for dopamine oxidation. The electrode operated best at working potential as low as -0.2 V (vs. Ag/AgCl). It responds linearly to dopamine within 0.25mM to 4mM concentration. The sensor has good selectivity, better stability, repeatability and reproducibility.Item Detection of Heavy Metal Ions using a Composite of Graphene Oxide, Iron Oxide and Metal Organic Framework(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-19) Farhan Nazir Ahmad; FA18-R06-005; Dr. Sara Riaz; LHR TP 6489Heavy metals are non-biodegradable, tend to accumulate in living organisms and cause serious health problems. Therefore, effective treatment of heavy metal ions in aqueous media is critical for public health. For selective and sensitive detection of Pb+2, Hg+2 and Cu2+, glassy carbon electrode was modified by a composite of Graphene oxide, metal organic framework and iron oxide. GO serves as backbone of MOF and iron oxide. It improves conductivity by enhancing electron transfer rate in matrix. Moreover, there are interactions between hydrophilic groups of GO and metal cations. GO, MOF and composite of GO-iron oxide was characterized by FTIR and XRD. The detection performance of electrode modified by composite of GO-MOF-iron oxide and GO-iron oxide was explored by EIS and CV. On introduction of MOF-5 to composite of GO-iron oxide, MOF-5 blocks active sites of composite and deactivate it, as MOF-5 hinders transfer of electron. While composite of GO-iron oxide shows excellent heavy metal ions adsorption, high capacitive current and better sensitivity as compared to composite of GO-MOF-iron oxide. This is all attributed to better electron transport properties, good electronic conductivity and large surface area of GO-iron oxide which lead to excellent catalytic response towards heavy metal ions.Item Growth of ZnO NanoFlakes on Flexible Carbon Based Transducer Surface for Electrochemical Sensing of Acetone(library Information Services CUI Lahore Campus, 2020-02-16) Seemal Mansoor; FA18-R06-026; LHR TP 5967; Dr. Sara RiazThe present study was concentrated to develop a rapid, electrochemical, selective, cheap and easy to use carbon cloth (CC) based assay for the quantitative and qualitative detection. CC was fabricated with a ZnO nanoparticles first and then with diazonium salt. This modified CC was then applied for the detection of acetone. FTIR, AFM and SEM was used to explore the chemical and physical characteristics of CC of before and after each modification. These results manifested that ZnO-nanoflakes and diazonium salt functionalization could increase the roughness of the CC surface that was advantageous to promote the interaction between CC and analyte to be detected. Linear sweep voltammetry and cyclic voltamogram were used for electrochemical analysis. The proposed electrochemical sensor was analyzed for various concentration of acetone. To validate the concept, the proposed sensor was assessed for higher concentrations of acetone in different ways. Among them, ZnO nanoflakes/ CC which was modified with diazonium salt showed better response (in acetone solution alone) than ZnO nanoflakes /modified CC (in the solution of diazonium salt and variable concentrations of acetone)Item Synthesis and Characterization of Dipyromethanes and Their Metal Complexes for Glucose Detection(library Information Services CUI Lahore Campus, 2020-02-16) Adeel Ahmed; FA18-R06-013; Dr. Sara Riaz; LHR TP 5964Glucose plays an active part in human body such as balancing the body in non-fortified feature, generating energy and improve memory enlargement. Blood glucose concentration is a universal benchmark of a patient’s fitness, particularly for threatening mark related with diabetes mellitus. Due to increased numeral of diabetic patients, various methodologies for glucose determination have been employed to assist precise and uninterrupted glucose detection. In present work, an advanced enzyme free electrochemical device has been proposed for glucose measurements. We intended to synthesize various derivatives of Dipyromethanes (DPM) via microwave assisted synthesis for the detection of Glucose. The synthesis of DPM is generally acid catalyzed reactions that occur in the existence of organic solvent dichloromethane (CH2Cl2). However, the problem of refinement and separation associated with conventional synthetic routs limits their synthesis and utilization in numerous fields. To avoid the lengthy and time consuming process of crystallization and separation we aim to further synthesize their transition metal complexes with Zn. The complexes of DPMs were purified via simple centrifugation. These DPM complexes were further drop casted onto carbon based electrodes (preferably glassy carbon electrodes) to study their electrochemical properties. For this purpose, the electrochemical biosensor was prepared by the modification of a freshly glassy carbon electrode surface with zinc-dipyromethanes complex. The spectral studies were done by UV-visible spectrophotometer and fluorescence spectrophotometer. The surface morphology and structure of the prepared complex were analyzed by AFM, FTIR, and XRD. The electrochemical characteristics of the complex were evaluated by CV and EIS. The results of CV (oxidation peak at 0.33V) indicated that zinc-dipyromethanes complex (Zn-DPM) can efficiently oxidize the glucose without any enzymes assistance and can further be used for glucose detection.Item Preparation of Hydrogel-Based Electrolytes for Flexible Supercapacitor Electrodes(2025) Sunaina Ahmad CIIT/FA23-R06-024/LHR; Dr. Sara Riaz; LHR TP 9695Energy plays a crucial part in every aspect of modern life, because of the traditional energy storage devices as well as the problem regarding endurance, the small and flexible energy storage devices are more widely used in recent times. Supercapacitor is an energy storage device with advanced applications, like specific capacitance, environmental friendliness, charging and discharging properties, extensive life-span power and energy densities. Conventional SCs used liquid electrolytes which were toxic and cause leakage in SCs. Researchers choose safer options by using hydrogel electrolytes. Hydrogels are three-dimensional network of polymer with incorporation of liquid molecules, hydrogels are leakage proof, electrochemically stable, less toxic and highly biocompatible. The performance of SCs was enhanced using gelatin and polyvinyl alcohol and ratios of polyphenols from green tea extract and potassium hydroxide. Hydrothermal method was used to prepare electrode material of core shell (ZIF8/ZIF67). Synthesis of hydrogel electrolytes was done by incorporating borate crosslinkers with polyvinyl alcohol and gelatine. Series of hydrogel electrolytes were synthesized, with different quantities of polyphenols. FTIR, contact angle and XRD techniques were performed to study hydrogel electrolytes. Then, by incorporating two electrodes and an electrolyte, a supercapacitor device was fabricated. To analyze the efficiency of the supercapacitor, GCD, CV, and EIS were performed.