Department of Physics
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Item Synthesis of Nickel Oxide (NiO) Fluorescence Nano Quencher and Their Application in Aptasensing of Ochratoxin-A(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Aqsa Khan; FA17-RPH -042; Dr. Rizwan Raza; LHR TP 5727The fabrication of fluorescence based biosensor for the ultra-sensitive and selective monitoring of Ochratoxin-A in the food samples is very important these days. We demonstrate for the first time, the development of nickel oxide nanoparticles (NiO) quenching based aptasensing platform for the detection of target molecule (OTA). In this work, NiO quench the fluorescence of FAM-labeled aptamer. These quenched intensities were due to energy transfer processes to the metal nanoparticles. Conversely, increase in fluorescence quenching intensities with a decrease in the size of the nanoparticles which may be useful for the design of new analytical tool to detect the presence of target analyte. The structural properties of prepared nano materials were analyzed by X- Ray diffraction (XRD).Surface morphology of prepared metal oxide nano materials were studied by Scanning Electron Microscopy (SEM) and crystalline behaviors size/shape was analyzed by RAMAN spectroscopy. We have found the cost-effective, easy to use and affordable method to design aptamer based fluorescence quenching assay for the detection and early diagnoses of mycotoxins (OTA).Item Theoretical and Experimental Study of Mixed Ionic Electronic Materials (MIEC) for Electrochemical Functional Nano-Composite Layer(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2017) Muhammad Khurram Qureshi; CIIT/FA15-RPH-014/LHR; Dr. Rizwan Raza; LHR TP 6984Due to the increased demand of energy there would be a stern dispute in the near future as the efficient energy resources are soon to be ceased. To overcome such a challenging disagreement, we have to put our attention towards such novel energy conversion and efficient technology which can strengthen us against such problem. Fuel cells are promising devices for clean and efficient power generation. The electrolyte free fuel cell (EFFC) is an innovative, high-energy conversion and efficient generation of fuel cells which directly convert the chemical energy into electrical energy. In this research the mixed ionic and electronic conducting material will be equipped by desired route for EFFC production. MIEC is basically responsible for the performance of EFFC. EFFC with only one homogenous layer Nano-composite material comprises upon ionic and electronic conductors which will overwhelm the mechanically and chemically compatible issues. The designed material was examined experimentally and theoretically. The single homogenous layer consist upon mixed conducting Nano-composite material certifies the better performance, high efficiency and reliability. Diverse electrochemical measurements are used to investigate the performance and efficiency of prepared EFFC material. The conductivity of MIEC is investigated with 2 probe and 4 probe method. After that, the mixed conductivity was separated out with the help of ion blocking and Heb-Wagner method. These two techniques were used to study the ionic and electronic conductivity of MIEC. Similarly, the optical, mechanical, vibrational, structural characteristics and important parameters were investigated with the help of multiple techniques The working and electrochemical performance of prepared EFFC was studied at Nano level to explain the working principle of as prepared EFFC. Theoretical model and simulations of pItem DEVELOPMENT OF ELECTRODE MATERIALS FOR FUEL CELL USING PULSED LASER DEPOSITION(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2017) IMRAN ALI; CIIT/SP15-RPH-012/LHR; Dr. Rizwan Raza; LHR TP 6845The prevailing energy crisis in the world has to be tackled by employing sustainable energy sources. In recent years, research has been conducted on solid state ionic devices such as fuel cells, lithium ion batteries and solar cells which could be the future alternate energy storage and conversion technologies with no environmental issues. It has been observed that solid oxide fuel cells SOFCs with electrodes layers on electrolyte using Pulsed Laser Deposition PLD as compared to other fuel cells yield better results i.e. they can operate at intermediate temperature have high conductivity and enhanced power density. This thesis gives an approach to develop nanocomposite electrode materials for SOFCs to lower the operating temperature of SOFC. Lithium Nickel Copper Oxide (LNC), Lithium Nickel Copper zinc Oxide (LNCZ) and Samarium doped Ceria (SDC) nanocomposite have been synthesized using solid state reaction method and wet chemical method. The structure and morphology of nanocomposite electrode was examined by X-Rays Diffraction (XRD) and scanning electron microscopy (SEM). Atomic Force Microscopy (AFM) is used to examine the roughness and surface morphology of pulsed laser deposited film. The fuel Cell Performance was tested at temperature (550-7000 C). The Conductivity of the sintered nanocomposite measured by a two probe DC method. XRD pattern of the samples show that the materials are nanostructures. SEM images expose the morphology of materials which are homogenous and porous. Electrochemical study of synthesized fuel cell shows a mixed conductivity of 1.3 Scm-1 at 6500C. The electrochemical Performance of LNC/SDC/LNC configuration was measured with OCV 0.80V, Current density 400 mAcm-2 and power density 108 mW/cm2 with hydrogen fuel at 6500C. Whereas OCV 0.80V, Current density 408mAcm-2 and power density 118 mW/cm2 were observed at 6500C for LNCZ/SDC/LNCZ configuration using hydrogen as fuel and air as reduction agent at cathode terminal.Item Direct Internal Reforming of Methane Fueled Solid Oxide Fuel Cell by Effective Catalyst(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2017) MUHAMMAD UMAIR; CIIT/SP16-RPH-001/LHR; Dr. Rizwan Raza; LHR TP 6994Fuel cell is a device that produces power through chemical reaction without combustion. It is more effective among other source of energy. It is an environment friendly low or zero emission, high productivity, multi-fuel capacity, versatility. In this project, the work is done on the catalytic study of Solid Oxide Fuel Cell (SOFC). In SOFC, the most commonly materials are used ceramic based materials e.g. for electrolyte Yttria-Stabilized Zirconia(YSZ) but it require high working temperatures (700– 1000 °C) and can be keeping running on different fuels including natural gas. In this project, the electrode (LiNiCuZnFeO) is prepared by Solid State Reaction (SSR) method. The compatible electrolyte (LNK-SDC) is prepared by co-precipitation method. Three catalyst of different molar ratio of Barium Nickel Cobalt [Sample no.1 (Ba0.2Ni0.4CO0.4O3), Sample no.2 (Ba0.2Ni0.6CO0.2O3), Sample no.3 (Ba0.2Ni0.2CO0.8O3)] are prepared for direct internal reforming of SOFC using sol-gel method. Natural gas is used as a fuel for SOFC. The best performance of the cell is achieved at 650℃ with Sample no.2 (Ba0.2Ni0.6CO0.2O3) with maximum open circuit voltage (OCV) of 0.7V, current density of 250 mAcm-2 and power density of 64mWcm-2 with highest conductivity of 0.42 S/cm.Item Synthesis of Catalyst for Direct Ethanol Fuel Cell and its Electrochemical Characterizations(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) NAZIM ALI EJAZ; CIIT/SP16-RPH-004/LHR; Dr. Rizwan Raza; LHR TP 6910Fuel cell is a device which uses to generate electric current by chemical reaction without any kind of combustion and noise. It is environmental friendly and more efficient among all the other energy devices. Now the increasing interest of direct alcohol fuel cell (DAFC) is emphasized as an alternate source of clean, cheap, reliable and minimal environmental impact energy. Mostly methanol is used as a fuel but due to its toxicity, alternatively ethanol is used as a fuel due to its some advantages like nontoxic and its availability from biomass resources. In this research, a suitable catalyst for direct ethanol fuel cell (DEFC) is synthesized, which increase the rate of oxidation of ethanol into CO2. The purpose of this work is to reduce the poisoning effect which will increase the activity of electrode. The operating temperature of direct ethanol solid oxide fuel cell (DESOFC) is within the range 600-1000°C. Three samples with different molar ratio are prepared Li0.1Ni0.5Cu0.1Ce0.3 oxides, Li0.1Ni0.5Cu0.2Ce0.2 oxides and Li0.1Ni0.5Cu0.3Ce0.1 oxides by sol-gel method. The best results are shown by Li0.1Ni0.5Cu0.1Ce0.3 oxides the highest conductivity is 0.27 S/cm at 750°C and power density 20 mWcm-2 at 700°C observed.Item Smart Nitrite Sensor for Real Time Food and Water Quality Monitoring ‒ Improving Public Health(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) AMINA SALEEM; CIIT/FA17-RPH-060/LHR; Dr. Rizwan Raza; LHR TP 5734In the preparation of CCE, SiO2 has been used as the support, due to its characteristics in forming very stable and mechanically resistant framework, resulting a porous structure of the support, a desirable characteristic in term of immobilization of electroactive species with good yield of surface density, silica has been the main component of the ceramic material. However, it is known that modification of the surface requires the presence of more active and reactive functional groups. On silica surface the reactive species are the silanol, Si-OH, groups. In this project the main objective is to study the synthesis, characterization and application of a new carbon ceramic, designated as SiO2/Al2O3/C (C= graphite). The technique of the conducting ceramic material was the sol-gel processing technique. The well characterized SiO2/Al2O3/C, modified with 3-n propylpyridinium silsesquioxane chloride functional groups, and tested as an electrochemical sensor of NO2 - in the environment. Nitrite plays an important role in environmental and biological processes, its monitoring is important since it is used as a food preservative against antimicrobial action. However, the presence of nitrite in food or drinking water can be hazardous to health, especially for infants and pregnant women, and, in the stomach, it can react with dietary components to form toxic and carcinogenic nitrosamines. The presence of nitrite in environmental samples, arising from industrial activities, indicates the extend of pollution and eutrophication of natural waters. So in this project, a novel nitrite sensor fabricated based on a SiO2/Al2O3/C/SiPy+Cl new conducting ceramic material. The degree of functionalization of the material determined by C, H, N elemental analysis and the local structure by 13C and 27Si SEM and diffuses reflectance Raman spectroscopies.Item Efficient Electrochemical Energy Conversion of Carbon from Coal and Waste(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) Amjad Ali; CIIT/SP14-PPHY-001/LHR; Dr. Rizwan Raza; LHR TP 5601Direct carbon fuel cell directly converts the chemical energy stored in the fuel (carbon) to electricity. It is a high-temperature fuel cell having practical efficiency of 80%, normally operates at or above 700 o C with significantly low CO2 emission compared to coal burning power plants which release large amount of notorious gases NO2, SO2 and CO2. In this PhD research work main objectives are to synthesize combination of efficient electrolytes and electrodes materials not only operational compatible with carbon fuel, but also are electrochemical stable, having high conductivity and should provide excellent performance. Further, this thesis is divided into three parts; Electrolytes, Electrodes and theoretical calculation. Therefore, commonly used co- precipitation technique has been employed to synthesize various electrolytes, calcium doped ceria, single carbonate- doped ceria, binary carbonate-doped ceria, and ternary carbonate-doped ceria, barium co-doped ceria, calcium co-doped ceria, magnesium co-doped ceria and strontium co-doped ceria. However, in addition to electrolytes mainly two types of electrodes known as oxides LiNiCuZnO (LNCZO), LiNiCuZnFeO (LNCZFO) and perovskite LaSrNiTiO3- (LSNT, LaSrFeTiO3- (LSFT, LaSrCoTiO3- (LSCT and LaSrZnTiO3- (LSZT have been prepared using sol-gel technique. The prepared materials are characterized using various structural techniques; X-ray diffraction (XRD), Scanning electron microscopy, Thermal analysis, UV-Visible spectroscopy, Raman spectroscopy, Fourier transforms infrared spectroscopy, DC/AC conductivity and electrochemical performance. On the top of all characterization the XRD results reveal the prominent cubic structure of all the electrolytes and perovskite electrodes, whereas composite structure of LNCZO and LNCZFO is confirmed. Moreover, two types of carbon fuel categorized as coal based (lignite, bituminous, sub-bituminous) and waste biochar (walnut shells, almond shells) have been used to evaluate the overall electrochemical performance of direct carbon fuel cell (DCFC). xi Amongst all the discussed electrolytes (Li,Na)2CO3–doped ceria(LN-SDC) has shown the highest ionic conductivity of 0.31 Scm -1 with maximum performance of 617 mWcm -2 in combination of LNCZO electrode at 600 o C for hydrogen as fuel and air as oxidant. Secondly the combination of co-doped ceria electrolyte calcium co-doped ceria (CSDC) and LNCZFO electrode had depicted the performance of 630mWcm -2 at 650 o C with hydrogen fuel, where as co-doped ceria electrolyte (CSDC) has shown highest ionic conductivity of 0.124 Scm -1 . Nevertheless in comparison above mentioned electrolytes LN-SDC with LNCZFO electrodes exhibited a performance of 58mWcm -2 for sub-bituminous fuel. Instead of obtained power densities of the cell comprised of cathode-electrolyte- anode (LSCF|LN-SDC|LSFT) are 78,73,57,29 and 26 mWcm -2 at 700 o C with fuel as sub-bituminous, walnut shells, almond shells, bituminous and lignite respectively. The prepared LSFT and LSCT also have been tested as cathode which shows good performance with carbon fuel. Further to elaborate, theoretical calculations using Density Functional Theory (DFT) technique are performed to co-relate the effect of structure, dopant radius, lattice constant of doped system, density of states and band gap with the experimental results and at some point both DFT simulation and experimental results have shown the best match in terms of increase in lattice constant by decreasing band gap.Item Development and Electrochemical Characterization of Nanocomposites for Biogas Based Fuel Cells(2018) Asia Rafique; CIIT/FA13-PPHY-003/LHR; Dr. Rizwan Raza; LHR TP LHR TP 5602There is an urgent need to explore affordable and renewable energy resources because of the decline in reserves of fossil fuels. Biomass is an abundantly available resource in nature and can be used to generate energy in a sustainable manner. Fuel cells deliver a combination of advantages and make use of renewable energy sources. Solid oxide fuel cells (SOFCs), specifically, overcome the petroleum scarcity issue by using biofuel. The aim of this thesis is the development of nanocomposite electrolytes and anode composite catalysts for low-temperature SOFCs fuelled with biogas for clean energy applications. In the present work, Sr/Sm-doped ceria (Sr-SDC) nanocomposite electrolytes with a core shell structure are synthesized with different compositions for low temperature SOFCs. A co-doping technique is successfully used to achieve a significant enhancement in the ionic conductivity of 0.50 S/cm at 600 ˚C for the nanocomposite electrolyte Sr0.1Sm0.1Ce0.8O2-δ-carbonate. The carbonate phase (shell layer) acts as a barrier and protects the SDC (core) from the partial reduction by the fuel. This carbonate shell introduces an interface between these two phases, which is the key to realizing the interfacial super-ionic conduction pathways. This work also describes the development of ceria electrolytes that are doped and co-doped with lanthanum (La) and zirconium (Zr) and show excellent thermal stability. The ionic conductivity of La0.2Ce0.8O2-δ (LDC), Zr0.2Ce0.8O2-δ (ZDC) and Zr0.2La0.2Ce0.6O2-δ (ZLDC) has been measured in the temperature ranges of 450 °C to 650 °C and LDC achieved a high ionic conductivity of 0.81 × 10-2 S/cm. Thermal expansion coefficients (TECs) of these electrolytes have also been found to have good concurrence and compatibility with commonly used electrolytes and electrodes. The main objective of this work is the development of stable and active anode catalysts that run over biogas as well as hydrogen for low temperature SOFCs. The anode composite Ni0.6Zn0.4- Gd0.2Ce0.8O2-δ (NiZn-GDC) has been developed that exhibits semiconductor conductive behaviour, and a maximum conductivity of 1.37 S/cm has been achieved at 600 ˚C. This composite anode is found to have excellent thermally stability as well as being carbon resistant to coking during testing with biogas. A maximum power density of xii 820 and 548 mW/cm2 has been reported with hydrogen and biogas fuels, respectively, at 600 ˚C. This thesis also describes Ni-based and Ni-free anode catalysts NiLiCu-oxide with LDC for SOFCs fuelled with biogas. The anode composite NLC622-LDC has reported a maximum DC conductivity of 3.47 S/cm with Pmax of 650 and 390 mW/cm2 for hydrogen and biogas, respectively, at 600 ˚C. A Ni free anode catalyst Zn0.2Li0.2Cu0.6O2-δ (ZnLiCu-oxide) is also developed as a potential candidate for biogas-based SOFCs that bypasses the difficulty of carbon deposition and has a maximum conductivity of 4.0 S/cm at 600 ˚C. An open circuit voltage (OCV) of 0.96 V is achieved with maximum power density of 600 mW/cm2 with biogas (50% methane) at 650 ˚C. In the present work, a theoretical model of FC system has been designed using MATLAB software, and it makes use of biomass (animal waste, redwood, rice husk and sugar cane). In the last part of the thesis, a partial research work has been conducted to cast the tapes of NiO-GDC (NiO-Gd0.1Ce0.9O1.95) as anode and GDC (Gd0.1Ce0.9O1.95) as electrolyte via aqueous tape casting method. The aqueous tape casting is an emerging and cost-effective technique for the commercialization of SOFCs but faces challenges with ceria tapes due to its poor mechanical strength and co-sintering of half-cells.Item Facile Synthesis of Nanostructured Bimetallic Mixed Oxides and their Electrochemical Characterization as Energy Storages Devices(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Muhammad Mudassir Hassan; CIIT/FA17-RPH-007/LHR; Dr. Rizwan Raza; LHR TP 5711Global warming is the major issue of our modern world. Thus, scientists and researchers are in search of more efficient and more environmental friendly energy materials. With the increasing development in the field of nanoscience and nanotechnology the modern world has transformed the old energy devices into more efficient and more sustainable energy devices. Therefore, there is a lot of need to find out more high performance energy storage devices. In this regard supercapacitor has a lot of potential to overcome the modern world Challenges. In this research work supercapacitor electrodes are prepared with improved energy density and power density. The material used in this research work for supercapacitor is Fe2(MoO4)3 which is a bimetallic mixed oxide. Sample is prepared by a facile hydrothermal method. The structural properties of the prepared sample are analyzed by the X-ray diffraction XRD. The XRD of the prepared sample shows the monoclinic crystal structure with average crystallite size of 68nm. To study the bonding between the atoms FTIR analysis is done. The results of FTIR shows the strong bonding between Fe and MoO4 ions. For electrochemical measurements 3 electrode system is used and two characterizations are done. CV of the prepared sample is done in two electrolytes to find out the best results. The CV curve shows the clear redox reactions occurring. As the scan rate is increased the current increases which confirms the fast electron transfer of electrons in the sample. GCD measurements shows that the sample has fast charging and discharging rate with excellent cyclability. The energy density and power density of the prepared sample was calculated to be 99.91 Wh/Kg and 5533.78 W/Kg respectively.