Department of Physics
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Item Production of Bio-Mimetic Nanoparticles for the Detection of Ascorbic Acid(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Nazar Ali; CIIT/SP24-RPH-018/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 10125An economical, sensitive and new approach based on colorimetric and UV- visible of ascorbic acid (AA) is developed. The mechanism of this method is the oxidation of 3,3',5,5'- Tetramethylbenzidine TMB with the material of the synthesis to create the oxidized TMB of a blue shade (ox-TMB). The ox-TMB is then reduced by the ascorbic acid leading to a decrease in the color intensity which can be both visually and quantitatively determined with the help of a UV Vis scanner. The main experimental parameters of the concentration of materials, TMB concentration, pH and concentration of the analyte were adjusted to improve sensing result. The most favorable conditions were found to be material concentration of 5µM, 0.5µM TMB and an acidic medium with a pH of 3-4. The response had a high reliance on pH indicating a change in color in an acidic conditions and no response at neutral and alkaline conditions (pH 7-11). The UV-vis absorbance at 652 nm under such optimized parameters reduced proportional to the change in AA concentration. High sensitivity was observed in the linear response in the concentration range of 2-5 nM where it had the lowest limit of 1.18 nM detection limit (LOD) and the highest limit of 3.59 nM was the quantification limit (LOQ). The technique proved to be very selective to the AA with minimum signal interference with the normal substances such as dopamine, glucose, cholesterol, urea, uric acid, amino acids, and the metal ions. The feasibility of the sensor was shown by using samples of diluted lemon and orange juice that were able to recover diluted samples of 97.98%-101.11%. To conclude, this has created sensing platform is easy, fast, accurate, and cheap, and therefore can be utilized in ascorbic acid detection in food samples and the future portable sensing platform is achievable.Item 3D Printing of Metal-Organic-Framework (MOF) on Fishery Packaging for Real Time Freshness Monitoring(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Muhammad; CIIT/SP24-RPH-005/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 10119The fabrication of colorimetric sensors via three-dimensional (3D) printing technology is an emerging field of research in recent times due to its cost-effectiveness, design freedom, and efficient use of sensing material. Herein, we utilize this technology to fabricate 3D printed multiplex tags (3D-PMTs) on textile fabric substrate to monitor real-time freshness of packaged fish. We prepare three sodium alginate (SA) based inks containing: rose anthocyanin incorporated metal-organic framework (RA-MOF) (pH indicator), curcumin incorporated metal-organic framework (Cur-MOF) (pH indicator), and silver nanoparticles (Ag NPs) (H2S indicator), respectively. We demonstrate that the incorporation of these indicators into the cross-linked sodium alginate (SA) does not affect their colorimetric response towards pH change and H2S. The 3D-PMTs exhibited excellent sensitivity, colorimetric response, and stability. These characteristics of the 3D-PMTs enable us to visually monitor the freshness of the packaged fish at three different storage temperatures (30°C, 16°C, and -4°C) for a prolonged period of time. The results demonstrate that these 3D-PMTs have great potential to be utilized in freshness monitoring.Item Effect of CO-Solvent Mediated Metal Ion Linker on Morphology and Electrochemical Performance of GO/PANI Hybrid(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2023) ATIQA SHAHZAD; CIIT/FA21-RPH-033/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 8772In this study, the morphology of the GO/PANI composites will be investigated as electrode materials for storage devices like batteries and supercapacitor by preparing the nanocomposites via wet chemical facile synthesis with an appropriate selection of co-solvents and a variety of metal ion cross linkers. The structural and morphological characterizations including Xray-diffraction (XRD), Raman spectroscopy and Scanning electron microscopy (SEM) will be performed to gain an insight into structural and morphological properties of the nanostructures. Whereas the cyclic voltameter was performed to study the charge storage and capacitance mechanisms in the structures. In this project the GO/PANI composites were synthesized via facile wet chemical method by varying three different metal ion linkers ZnCl2, NaCl2 and LiI2. The effect of metal ion linker onto the structural properties of the synthesized composites were studied using XRD and Raman spectroscopy technique. The XRD results confirmed the synthesis of GO and PANI composite. The broad peaks of (113) and (002) plane of PANI and GO shows the amorphous behavior of the synthesized composite. The crystallite size and interplanar spacing of the composites were estimated using Scherrer formula and Bragg’s equations. The estimated crystallite size for (113) and (002) plane of PANI and GO are 2.50nm, 5.60nm, 6.00nm and 2.00nm, 2.23nm, 2.50nm respectively. The estimated interplanar spacing for (113) and (002) plane of PANI and GO are 0.49nm, 0.43nm, 0.44nm and 0.39nm, 0.38nm, 0.37nm respectively. The Raman spectroscopy shows the characteristic vibrational modes of GO and PANI in pure and composite samplesItem Mxene and Graphene based Nano Composites for Energy Storage Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Tariq Ali; CIIT/SP21-RPH-024/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 8168With the rapid growth of the human population the energy crisis is also growing in the world. To address this problem, it is essential to design and fabricate energy conversion.and storage devices. Among all available energy storage devices, supercapacitors (SCs) have attracted more attention from the current research community because of their unique features. MXene is regarded as one promising candidate for supercapacitors due to its high electrical conductivity and volumetric capacitance. MXene is a newly developed two-dimensional (2D) material. It is a very suitable substrate for fabrication due to its high electrical conductivity and large specific surface area. The two-dimensional MXene (Ti3C2Tx) sheets stacked quickly, reducing their specific surface area and charge/mass transport properties. However reduced graphene oxide presumed as significant part to improve the electrochemical behaviour. Graphene combined with MXene resolve the restacking problem and promote rapid ion diffusion in electrode materials. In this project, the Mxene/rGO composite will be synthesized through simple and facile hydrothermal treatment. The manufactured nanocomposite will be used as efficient electrode material for energy storage devices such as supercapacitor. Also, the various samples of graphene oxide were prepared using different nitrates as precursors with varying recipes via Modified hummers method and Improved Hummers method. The proposed materials are GtO, XGO, Na-GO, Mn- GO, Cu-GO, Ni-GO, Zn-GO, GO, 5M-rGO, 10M-rGO and M-GO film. The prepared samples were characterized by different characterization techniques such as Raman, PL, FTIR, UV-VIS and Electrochemical Impedance Spectroscopy (EIS). Raman spectroscopy can be used to examine the chemical components of materials by detecting vibrational, rotational, and other modes in a molecular system. The Raman spectra shows the D, G and 2D bands attributing the defects states and successful oxidation of GO. The broad and asymmetric emission peaks ranging between 500-900nm were observed by photoluminescence spectra. The remarkable sharp emission peak at 600, 599 nm (visible range) for Cu-GO, Ni-GO and Zn-GO is caused by the presence of CO, C=O, and O=C-OH functionalized groups on the GO. The highest PL intensity is occurred at 717, 795 and 721 nm for GO, 5M-rGO and 10M-rGO indicating the red shift for all samples due to some extrinsic defects. FTIR technique is employed to study the chemical composition and its bonding. All the samples accommodate numerous functional groups like epoxy, carbonyl, hydroxyl, and carboxyl. The straight line in lower frequency portion indicates the capacitive behaviour of the electrode material. The EIS analysis investigated the charge transfer property and capacitive nature of the synthesised electrode material. From Nyquist plot of GO, Mxene 5M-rGO and 10M-rGO the slope of the curve decreases in the low frequency region demonstrating the fast ion diffusion/transportation properties. The observed band gap is 2.2eV, 1.53.9eV 2.19eV and 1.6- 3.43eV for GO, Mxene, 5M-rGO and 10M-rGO. It is indicated that all the samples show good absorption in the visible range (300-800nm). The main peak at round about at 230 nm represents the π-π* transitions of C=C bond. The shoulder peaks at round 330 nm stands for n-π* transitions of C=O bonds. Thus, the fabricated Mxene and graphene- based nanocomposite offer to be a promising material in energy devices with high energy. The cyclic voltammogram of our synthesized electrode material was compared with individual materials worked as electrodes at same potential window and scan rates and in same electrolyte as mentioned above. The shapes of CV curves for GO and Mxene were found to be approximately rectangular and symmetric, even at high scan rates, demonstrating excellent capacitive behaviour and rate performance. The CV curve for 5M-rGO can be observed to be well almost rectangular, revealing that it can serve as best electrochemical double layer capacitor (EDLC) electrodes.Item Study of Structural, Thermoelectric and Electrochemical Analysis of LaSrCoFeO Cathode Materials Prepared by Different Methods(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Khadija Imdad; CIIT/FA20-RPH-044/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 8000World is moving towards renewable energy sources to avoid carbon dioxide emission causing global warming and climate change. Solid oxide fuel cells SOFCs are one of the best alternatives for energy production due to its maximum energy conversion and zero/low emission. To use biogas as a clean and high energy conversion, SOFC is the good option. However, there are still some complications that need to be addressed; one of the significant challenges, activity of SOFC at low temperature is decreased because of interfacial polarization obstructions and also oxygen reduction reaction (ORR). Thus, to improve the activity and ORR, Lanthanum based perovskite structured cathode materials were synthesized. The proposed materials were Lanthanum Strontium Cobalt Ferric oxide (La1−xSrxCo1−yFeyO3–δ (LSCF)), where x=0.3 and y=0.7. Samples were prepared by different methods such as: sol-gel method, co-precipitation method, solid state reaction method and ball milling method. The structural properties were analyzed through Raman, FTIR and XRD.UV visible analysis were also implemented to check the direct and indirect band gap of La0.7Sr0.3Co0.3Fe0.7O3-δ prepared by different methods. Electrical Impendence Spectroscopy was uses to check the conductivities of the prepared samples at different temperatures. Results revealed the Rhombohedral Structure of LSCF belongs to the R3c space group. FTIR Spectra shows the absorption peaks at 650cm-1, 656cm-1, 657cm-1, is due to the stretching vibration of Co-O/Fe-O in LSCF perovskite structure. The maximum conductivity was obtained 0.08 S/cm at intermediate temperature of LSCF which was prepared by Co Precipitation Method. This suggests that resistance lowers as temperature rises, leading to an increase in conductivity and ORR as well. La0.7Sr0.3Co0.3Fe0.7O3- δ, which was made using the co-precipitation method, has a direct band gap of 2.51 eV. This sample has the lowest band gap of all the samples made using various methods. AC conductivity is measured by four-point probe spectroscopy for the LSCF cathodes. The data obtained from four-point probe spectroscopy electrical conductivity for all prepared cathode sample is calculated At Intermediate temperature (500°C) material with different methods such as sol-gel, co- precipitation, solid state reaction and ball milling give maximum conductivity such as 0.049,0.0889,0.0250 and 0.0159 respectively. The La0.7Sr0.3Co0.7Fe0.7O3–δ has maximum conductivity of 0.0889 Scm -1 at 500 °C prepared by co-precipitation method. The maximum value of OCV and current for the prepared pallets are 0.53V and 0.011A respectively. Whereas the maximum value of current density and power density is 17.18mA/cm2 and 2.88mW/cm2 respectively at 600℃.Item Study of Quantum Effects and Porosity of the Perovskite Materials for Energy and Photocatalysis Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Asifa Kusar; CIIT/FA20-RPH-007/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 7972Energy conversion devices are widely being used to convert chemical into electrical. Fuel cell is the most prominent candidate among all the energy conversion devices. The operating temperature of conventional fuel cell is very high because of high electrolyte resistance. Develop better energy storage and conversion devices is the main goal of the scientists and engineers because of increasing global temperature due to consumption of fossil fuels. Fuel cell has potential and capability to give maximum energy without deteriorating environment. Electrode is the most important component of fuel cell because reaction takes place on it. Lanthanum and ferrite-based perovskite material are investigated quantum mechanically to find out the impact factor on working of SOFCs. Among the prepared samples the material with high concentration shows batter crystal structure, photocatalytic activity and improved conductivity. Samples have been investigated by various techniques showing considerable porosity, stability and Prescence of reactive metal cations like La+2, Sr+1, Cu+1 , Fe+2 and Fe+3 reveal the improved functionality of perovskites as they assist in conductivity, oxidation, reduction and catalytic process. Crystalline structure of the material is determined by XRD, energy band gap can be found by UV-Vis, vibrational characteristics and phase shift of the synthesized material can be found by Raman spectroscopy, materials used in synthesis can be confirmed by FTIR. Among various types of perovskites, the LSF perovskites are best performing material for photocatalytic applications while study of quantum effects reveals that LSCF second to them LCF are best optimized material for energy applications.Item Development of GO-MnO2 Nanocomposite based Electrode for Energy Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Mariyam Ashraf; CIIT/SP20-RPH-036/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 7717Transition metal oxides exhibit unique properties as catalytic activity, piezoelectricity, and superconductivity and are widely used in energy storage and conversion devices. For energy storage and transfer devices like supercapacitors and batteries have been widely researched on the purpose of obtaining desirable performances. In this work, Manganese based oxide materials synthesized by Modified Hummers method, hydrothermal method and sol-gel technique respectively and their functionalities are investigated as electrode function of supercapacitor devices. The perposed materials are GO, MnO2, GO-MnO2, Li (0.1) doped MnO2 and Li (0.2) doped MnO2. Their investigations consist of various characterizations such as XRD, Raman and FTIR. The XRD pattern of MnO2 (JCPDS: 44-0141) having tetragonal structure. The average crystallite size of MnO2 is 24.34 nm. In XRD pattern of Li (0.1) doped MnO2, the cubic structure of the Mn-O confirmed with JCPDS card: 96-201-9466, average crystallite size (D) is 28.93 nm and the cubic structure of the Li-O confirmed with JCPDS card: 96-151-4099, average crystallite size (D) is 31.09 nm. The orthorhombic structure of the LiMn-O confirmed with JCPDS card: 01-081-1706 and average crystallite size (D) is 22.16 nm. FTIR technique is employed to study the chemical composition and its bonding. All the samples accommodate numerous functional groups like epoxy, carbonyl, hydroxyl, and carboxyl. Raman spectroscopy is used to detect vibrational, rotational, and other states in a molecular system, capable of probing the chemical composition of materials. Electrochemical performance of prepared electrodes was evaluated by cyclic voltammetry (CV), galvanic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements. The specific capacitance, energy density and power density for GO-MnO2 electrode are 861 Fg-1 at 1Ag-1, 0.0298Whkg-1 1Ag-1, and 0.00948Whkg-1 1Ag-1 from GCD curve. From Nyquist plot the MnO2 shows good electrical conductivity as compared to GO-MnO2 and when replace Li with GO the conductivity increased by increasing the ratio of doping material. It is concluded that the electrode material shows good specific capacitance with small value of energy and power density. A computational approach is also used to analyze the thermometric properties such as Seebeck coefficient (S (T)), electrical conductivity (σ (T)), thermal conductivity (k(T)), power factor (P (T)), and figure of merits (Z (T)) by software Quantum espresso using Plane-wave approximation which shows that MnO2 having excellent thermoelectric properties.Item Synthesis of Metal-Organic-Framework Derived Materials for Energy Storage Applications(2021) Ayesha; CIIT/FA19-RPH-026/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 7267With the progress in industrialization, the scarcity of resources and environmental pollution is growing fast. On the one hand, carbon dioxide produced by the ordinary combustion vehicle is a major source of global warming, where the fuel cars are accounted to consume a huge amount of oil resources. On the other hand, as the world has realized the importance of environmental protection, the development of a low- carbon transportation system has become an important solution. The electric vehicle has brought a lot of benefits, such as environmentally friendly, clean and no pollutant emissions. As a result, it might be regarded a potential new energy vehicle that has piqued the interest of consumers, industry, and researchers. Supercapacitors were also known as ultra-capacitors are being evaluated as one of the viable energy storage choices for future generations. These gadgets have been found to be useful in a range of applications, namely powering hybrid electric/electric automobiles and other electrical and electronic devices that enable energy to perform. Supercapacitors are the most flexible devices, widely used for supplying electrical energy quickly and in applications that need a long shelf life. As a result, there are considerable market demands for supercapacitors' development, and long-term advancement is necessary for their successful improvement and commercialization. New electronic and optoelectronic gadgets have recently grown on the market, requiring more dependable power sources with higher energy density and longer duration. Owing to their, pollution-free nature, stability, and high power density, supercapacitors have emerged as feasible options for energy storage. Traditional supercapacitors' poor energy density prevents them from being widely used, leading researchers to look into new forms of supercapacitors with better performance. Increasing the electrochemical performance of supercapacitors through the development of innovative electrode materials has been a major focus of study in recent decades. Asymmetric supercapacitors (ASCs) made consisting of two different electrode materials have a large working voltage window, enabling them to substantially increase energy density. In this research work, asymmetric super-capacitors electrode (ASCs) has been fabricated using Metal-Organic-Frameworks (MOF) derived mixed metallic oxides @CC as a positively charged electrode and MOF-derived nanoporous carbon (NPC) based material as a negatively charged electrode by a cost-effective hydrothermal method. The substantial materials are zinc-cobalt nitrates and 2-methylimidazole. The hydrothermal method is used to produce all samples.Item The Electrochemical Role of Mixed Valence Manganite for Fuel Cells(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Bushra Bibi; CIIT/FA19-RPH-011/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 7261In this era renewable energy sources are becoming more important. They will play and anticipate a more vital role in near future to avoid atmosphere changes. In this context, fuel cells have gained much attention due to their high conversion efficiency when contrast with conventional energy conversion system. Among all the fuel cells, solid oxide fuel cell (SOFC) is one of the best sources for energy conversion technologies along with low toxic emission, pollution, fuel flexibility, and cost effective materials characteristics. However, there are still some complications that need to be addressed; one of the significant challenges, activity of SOFC at low temperature is decreased because of interfacial polarization obstructions and also oxygen reduction reaction (ORR). Thus to improve the activity and ORR, Strontium substituted lanthanum Manganite La1-xSrxMnO3 perovskite type cathode materials is synthesized. The prepared materials are Strontium substituted lanthanum Manganite (La1-xSrxMnO3) (LSM)) where x=0, 0.2, 0.4, 0.6, 0.8, 1.0 All samples are prepared by sol gel method. The functionalities of cathode materials (La1-xSrxMnO3) (LSM)) is investigated in this research. Prominent bands at peak positions 310, 456, 643, 990 cm −1 wavelengths are observed through Raman spectra of LSM cathodes, analogous to Mn-O-Mn bonds typical stretching, asymmetric stretching vibrations for Sr-O band. The prominent peaks at 650, 855, 1052cm -1 wavelengths observed through FTIR Analysis, these peaks attributed to stretching vibration of La-O bond, V1mode of carbonate ion, symmetric vibration of Sr-O bond. The band gap energy of material has been calculated 4.18 eV, 4.2 eV, 4.19 eV and 4.21 eV of La1Mn1O3, La0.8Sr0.2Mn1, La0.6Sr0.4Mn1 and La0.4Sr0.6Mn1respectively. These show that the band gap increases with the increase of the Sr 2+ ions concentration. DC Conductivity measurements of LSM cathode samples are evaluated by four point probe method. The La0.8Sr0.2Mn1O3–δ (LSM)has maximum conductivity of 0.726 Scm -1 at 600 °C .The effects of synthesized LSM materials on performance for Solid Oxide Fuel Cell (SOFC) cathode were studied. The results indicate that developed LSM materials are good cathode for SOFC as they have adequate electrocatalytic properties and good chemical stability.Item The Investigation of Electrolytic Properties of Silicon Carbide for Fuel Cell(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muddasir Ammar; FA16-BPH-055; Dr. Muhammad Ashfaq Ahmad; LHR TP 5931This report is devoted to the synthesis of silicon carbide based composite as an electrolyte material for fuel cell. As fuel cell is an efficient device due to its clean energy production. To enhance the efficiency of such type of clean energy devices an efficient electrolyte material is required for its proper working. Silicon carbide is well known because of semiconductor and excellent potential in energy devices due to its better electrical and mechanical properties. It has maximum avalanche breakdown, best thermal conduction, non-oxide behavior, high melting point. In this research project Si-C composite was synthesized by solid state reaction. To study the structural properties of the synthesized samples XRD has been carried out and find out the crystallite size average 28.069nm. Through 4-probe method measured its electrical conductivity which was 0.4Scm-1at 700oC. Then fabricate three-layer pellet like device for fuel cell. Using SiC as electrolyte material, and LNCZ as electrode material. By providing hydrogen as a fuel measure electrochemical behavior of cell. The highest power density was 36 mWcm-2, and maximum 0.68V open circuit voltage.