Browsing by Author "Dr. Muhammad Ajmal Khan"

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Controlled Synthesis of Nickel Doped Molybdenum Oxide for High Performance Supercapacitors
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Surraya Sameen; CIIT/FA17-RPH-003/LHR; Dr. Muhammad Ajmal Khan; LHR TP 5709
NiMoO4 nanocomposite for supercapacitors have successfully developed via hydrothermal method at 120oC for different time (6h, 7h, 21h) for making 3 samples. Synthesized materials is suitable for psuedocapacitors because it sores charge via redox reactions during charging and discharging. Nickel doped molybdenum oxide materials in composite form has been used for super capacitors analysis in order to take the benefit of high-performance stability and capacitance. Electrochemical properties were investigated by using KOH as an electrolyte solution. FTIR shows the flexing, stretching, and antisymmetric bonding present in nanocomposite between molybdenum and nickel. NiMoO4 heat treated at 21 hours considered best due to less charge and discharge cycle time determined by GCD. Hight specific capacitance shows the better performance of prepared NiMoO4 that treated for 21 hours. CV shows the material have pseudocapacitive behavior and large potential window belong NiMoO4 with higher current range which makes it functional.
Development of Lanthanide Incorporated Strontium Cobalt Cathode for Energy Conversion Devices
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) MUHAMMAD AQEEL AHMAD SHAKER; CIIT/SP19-RPH-023/LHR; Dr. Muhammad Ajmal Khan; LHR TP 7233
In the modern age of science and technology every system of manual work is transferring to machines to run the these machines energy is required, so the need of time is motivating researchers to enhance their activities in the field of renewable energy production devices which will be able to produce more energy at very low cost. In this regard fuel cell got higher attraction of investigation due to its higher efficiency, environmentally friendly nature, and low cost. Solid oxide fuel cell (SOFC) is an extremely encouraging class of fuel cells. SOFC consists of electrolyte sandwiched between anode and cathode. In this research work, lanthanide based strontium cobalt oxide cathode materials are prepared by sol-gel method and their properties are characterized for the cathode functioning of solid oxide fuel cell (SOFC). The synthesized materials are Sr1Co0.8La0.2 (SCL), Sr1Co0.8Ce0.2 (SCC) and Sr1Co0.8Gd0.2 (SCG). These materials are investigated by various characterization X-ray’s diffraction (XRD), Fourier Transformation Infrared Spectroscopy (FTIR), Raman Spectroscopy, DC-conductivity by four probe methods. XRD characterization is used to conform the chemical composition, type of crystal structure and crystallite size. In the prepared materials Sr1Co0.8La0.2 (SCL) have the least crystallite size which is 19.8 nm. This material showed the best value for conductivity as the crystallite size is inversely proportional to the conductivity of the material. FTIR technique is used to study the chemical composition and its bounding. Existence of C-H, C-C, C=C, O-H either of bending or stretching nature is obtained against the wave number in each sample. In Sr1Co0.8La0.2 (SCL) peaks are found at 853 cm-1,859 cm-1 and 1426 cm-1 which are corresponding to Sr-O, La-O and Co-O respectively. In Sr1Co0.8Ce0.2 (SCC) peaks are found at 703 cm-1, 988 cm-1, 1433 cm-1, 1695 cm-1 and 1746 cm-1 which are attributed to Sr-O, Ce-O,CO-O, Ce=Ce and Ce=O respectively. In Sr1Co0.8Gd0.2 (SCG) peaks are observed at 856 cm-1, 950 cm-1 and 1441 cm-1 which belong to Sr-O, Gd-O and O=Co respectively. For Sr1Co0.8La0.2 (SCL) peaks are found at 157 cm-1, 525 cm-1, 957 cm-1 and 1363cm-1. The peaks at 157 cm-1 and 525 cm−1 wavelengths are analogous to O-B-O typical vibrations. The peak at 957 cm−1 wavelength correspond to B-O bonds stretching vibrations. For Sr1Co0.8Ce0.2 (SCC) peaks are found at 143 cm-1, 950 cm-1 and 1078 cm-1. The peaks at 143 cm−1 wavelength analogous are to O-B-O typical vibrations. The peaks at 950 cm-1 and 1078 x cm−1 wavelength correspond to B-O bonds stretching vibrations. For Sr1Co0.8Gd0.2 (SCG) peaks are found at 141 cm-1, 296 cm-1,649 cm-1, 939 cm-1, 1086 cm-1 and 1344 cm-1. The peaks at 141 cm-1, 296 cm-1 and 649 cm−1 wavelengths are analogous to O B-O typical vibrations. The peaks at 939 cm-1 and 1086 cm−1 wavelength correspond to B-O bonds stretching vibrations. The prepared cathodes shows strong peaks in the range of 700 cm-1 to 1800 cm-1. The peaks are attributed to C-H, C=O, O-H and C=C which are the main bonds present in oxides base cathodes. The electrical DC conductivity of prepared cathode Sr1Co0.8La0.2 (SCL), Sr1Co0.8Ce0.2 (SCC) and Sr1Co0.8Ce0.2 (SCC) was measured by four probe method in the temperature range of (300-600) oC in the presence of methane as a fuel in air environment. Conductivity is increasing with the increase in temperature. The highest values conductivity of all the prepared materials are obtained at 600 oC. Among all the synthesized materials Sr1Co0.8La0.2 (SCL) is showing the best value of conductivity 10 S cm-1 at 600 oC.
Efficient Strategies to Enhance the Conductivity in Perovskite Materials for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC)
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) MUBEEN YOUSAF; CIIT/FA19-RPH-055/LHR; Dr. Muhammad Ajmal Khan; LHR TP 7676
Renewable energy sources are growing increasingly essential in this day. In order to avert climate change, they will play and expect a more important role in the near future. Fuel cells have gotten a lot of interest in this context because of their high conversion efficiency when compared to traditional energy conversion systems. Solid oxide fuel cells (SOFC) are one of the finest energy conversion technologies available, with minimal hazardous emissions, pollution, fuel adaptability, and expense materials properties. However, there are still some issues to be resolved; for example, the activity of SOFCs at low temperatures is reduced due to interfacial polarization blockages and also the oxygen reduction process (ORR). Lanthanum Iron Copper Oxide Cathode materials are created to increase activity and ORR. The cathode materials La1Fe1-xCuxO3–δ where x= 0.1, 0.3, 0.5 and 0.7 are synthesis by sol gel method. Their characteristics are investigated by various characterizations such as Raman Spectroscopy, Fourier Transformation Infrared Spectroscopy (FTIR), X-Rays Diffraction (XRD), and Electrochemical Impedance Spectroscopy (EIS). Prominent bands at peak positions 158, 290, 305, 960 cm −1 wavelengths are observed through Raman spectra of La1Fe1-xCuxO3–δ at x = 0.1, 0.3, 0.5 and 0.7 cathodes, analogous to lanthanum site vibration, typical stretching, symmetric stretching vibrations for Cu-O band, phonon mode, octahedral tilt vibrations, D band and associated with Ag and Bg double energy band. The prominent peaks at 675, 855, 1056, 1458, 1645 and 2830 cm -1 wavelengths observed through FTIR Analysis, these peaks attributed to stretching vibration of La-O bond, Cu-O stretching vibration, bending vibration of C-H in gaseous, asymmetric and symmetric O-C-O stretching vibrations, bending mode of H-O-H bond vibrations. XRD also provide crystal structure of materials. Two cards from La1Fe0.9Cu0.1O3–δ (JCPDS card number 96-100-8543) and (JCPDS card number 96-901-4244) have an orthorhombic structure. Two cards from La1Fe0.7Cu0.3O3–δ (ICSD card No 96-900-2333) and (ICSD card No 96-100-8573) shows an orthorhombic structure. Two cards from La1Fe0.5Cu5.5O3–δ (ICSD card No 96-901-5232) and (ICSD card No 96-200-2184) show an orthorhombic structure. Two cards from La1Fe0.3Cu0.7O3–δO3–δ (ICSD card No 96-100-8930) and xi (ICSD 96-200-1419) describe hexagonal and orthorhombic Structure. Electrochemical Impedance Spectroscopy is use to analyze the electronic and ionic behavior of the material. Material La1Fe0.3Cu0.7O3–δ has good electronic behavior and enhanced the maximum ORR of material.
Electrochemical Properties of Bismuth (Bi) Doped Lanthanum Cobalt Iron (LCF) Oxide Material as Cathode at Different Sintering Temperatures
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Tehmina Rafaqat; CIIT/FA20-RPH-019/LHR; Dr. Muhammad Ajmal Khan; LHR TP 7981
To reduce carbon dioxide emissions, which create global warming and climate change, the world is moving toward renewable energy sources. Solid oxide fuel cells are one of the most effective energy generation technologies because of their high energy conversion and minimal influence on the environment. In this research work, we are synthesized the bismuth doped lanthanum cobalt iron oxide Bix (La0.6Co0.3Fe0.1)1-x (BLCF), where x= 0.1, 0.2, 0.3, & 0.4 cathode materials are prepared by sol-gel method and sintered (700-900) oC. The cathodes materials are characterized with various techniques such as for oxidation reduction reaction (ORR) by Electrochemical Impedance Spectroscopy (EIS), to examine the functional groups by Fourier Transformation Infrared Spectroscopy (FTIR), structural and vibratory properties through Raman Spectroscopy, energy band gaps by Uv-Vis Spectroscopy. The electrical conductivity and electrochemical performance are also studying at different temperatures. The composition Bi0.4(La0.36Co0.18Fe0.06)-oxide shows maximum oxidation reduction reaction (ORR) and good electronic behavior. The maximum conductivity is obtained Bi0.4(La0.36Co0.18Fe0.06)-oxide at 700 °C in air atmosphere and having the value 2.75 S/cm. FTIR spectra of cathodes materials B(LCF) show the peaks at 653, 994, 1097, and 3600-3855 cm-1 having different modes and bond (stretching of C-C) , Co-O, O-H bonding and vibrational peaks). Raman spectra represent the prominent bands at 310, 418, 635, 993 cm-1 related to the La-O vibration, Fe-O vibration, Co-O vibration, and Ag and normal modes. Band gap values decreased with increase in the temperatures and 4.00 eV at 700 °C and 3.53 eV at 900 °C, which indicate the semiconductor nature of the prepared materials. These results revealed that the BLCF cathode materials show high conductivity at intermediate temperatures. This makes it useful for SOFC application.
Experimental / Theoretical Approach for the Study of Nanocomposite Oxides (X-Co2O4, where X = Mn, Li, Ce) in Energy Applications
(2023) MUHAMMAD BILAL BUTT; CUI/SP22-RPH-027/LHR; Dr. Muhammad Ajmal Khan; LHR TP 8787
The study explores the potential of Nanocomposite Oxides (X-Co2O4, where X = Mn, Li, Ce) in energy applications, synthesized using a ball milling technique due to its efficacy in producing homogeneous nanoparticles with desirable electrochemical properties. The physicochemical and electrochemical behavior of the synthesized materials was revealed through various characterizations. Cyclic voltammetry (CV) and Galvanostatic charge-discharge (GCD) measurements gave some understanding into the electrochemical supercapacitor performance of these materials. They proved that they might be materials for supercapacitor electrodes. The synthesized samples' pseudo behavior was shown by the CV analysis performed on the assessed cycled material at different potential ranges and scanning rates ranging from 10 to 60mV/s. Galvanostatic charge discharge (GDC) reveals the sample’s duration and performance at various current densities. The maximum specific capacitance of 75 Fg-1 at a current density of 0.5 A/g is revealed by MnCo2O4. Particularly, EIS analysis provided the details of ohmic resistance within the samples which were used to find out the values of the conductivity. UV- visible spectroscopy reveals the optical band gaps of MnCo2O4, CeCo2O4, and LiCoO2 nanocomposite oxide materials are revealed to be 1.6 eV, 1.8 eV, and 1.9 eV. Several functional group evaluations for these materials were provided by Fourier-transform infrared spectroscopy, which contributed to a thorough understanding of their characteristics and possible uses. The Raman spectra display two main peaks of MnCo2O4 at 316 cm-1 and 672 cm-1, which are indicative of unique vibrational modes. CeCo2O4-related peaks may be seen at 463 cm-1 and 672 cm-1, while LiCoO2-related peaks can be found at 475 cm-1 and 578 cm-1. These peaks indicate the distinct metal-oxygen bonding and structural features present in each material. These findings provide important new information about the vibrational modes and composition of the investigated nanocomposites. The tetragonal crystalline structures of the nanocomposite oxides are confirmed by specific patterns in their XRD profiles. MnCo2O4, CeCo2O4, and LiCoO2 have average crystallite sizes of 40.94 nm, 34.2 nm, and 37.5 nm, respectively. As such, every facet of the synthesis process and properties will contribute to the development of these oxide nanocomposite materials for diverse energy applications.
Fabrication and Characterization study of Micro Thin Film Electrolyte for the Solid Oxide Fuel Cell (SOFC)
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) RIZWAN ASGHAR; CIIT/SP20-RPH-033/LHR; Dr. Muhammad Ajmal Khan; LHR TP 7691
In this study, Calcium Doped Ceria (CDC) thin film is prepared by the two steps, in the first step calcium doped ceria (CDC) powder is synthesized by co-precipitation method and in the second step, the slurry of calcium doped ceria (CDC) with ball milling and then thin film is casting with help of Tape casting technique. The fabricated thin films were sintered in the range of temperatures (150-750) ℃, in an air atmosphere. Crystal structure revealed that thin film has a cubic fluorite structure, and its average crystallite size is in the range of (53-42) nm. Raman analysis of the thin film was done in the temperature range of 350-750℃. These results showed that CDC thin films have high oxygen vacancies as sintering temperature rises. Which was depicting the high conductivity of the thin film. These results were also verified by the Conductivity measurements. The increase in FWHM of main peaks of Raman spectra, with an increase in temperature resulting in reduction of the crystallite size. Which was also confirmed by XRD results. FTIR results showed the formation of the Ce-O bonds, OH stretching, etc. Furthermore, FTIR spectra of the thin film at various temperatures indicated that OH stretching decreased as temperature increased, indicating that moisture in the sample reduced. Uv visible analysis was done at two different temperatures, 150 and 750℃. Band gap values decreased with increase in the temperatures. It was 3.22eV at 750oC and 3.3eV at 150℃. The conductivity measurements showed that conductivity of thin film was increasing as sintering temperature rises. which was confirmation of Raman results. Thin-film showed the highest conductivity 0.052 Scm-1 at 750℃, the activation energy and electrical band gap calculated from the Arrhenius plot are 0.25 eV and 0.5 eV for the sample sintered at 750oC, respectively. EIS spectra thin-film sintered at 750℃ and 150℃ showed semicircle, which confirms the ionic behavior of the CDC electrolyte thin film. The ohmic resistance also decreased with an increase in the sintering temperature. These results revealed that the thin film shows high ionic conductivity at intermediate temperatures. Which makes it useful for SOFC application.
Oxygen Transport Properties and Electrochemical Characterization of perovskites' Based Sr-PrxFel-x/ Sr-XuxFel-x Cathode Material Fuel Cell
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2023) Raja Rehman; CIIT/FA21-RPH-008/LHR; Dr. Muhammad Ajmal Khan; LHR TP 8590
Humans require energy in the modern world. Energy must thus be taken into consideration if life is to continue [1]. In the current state of our everyday life, energy consumption is increasing daily. Every country needs energy to be prosperous [2]. The availability of energy determines a country's capacity for economic development. The world is dealing with several energy-related issues, and as population grows, so does energy demand [3]. Both the exponential rise in technology and the exponential expansion in people are to blame for the increase in energy usage. These days, we utilize energy in a variety of ways, including for systems in homes, companies, and industries as well as for communication, transportation, and other purposes. Fig (1.1) illustrates the annual global energy consumptio
Preparation and Investigate Electrochemical Properties of Co-doped Strontium Iron Titanium (SFT) for solid oxide fuel cell.
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Irfan Ullah; CIIT/FA18-RPH-042/LHR; Dr. Muhammad Ajmal Khan; LHR TP 6363
The synthesis of barium chloride and lanthanum nitrate doping with SFT based composite material as an effective cathode material in solid oxide fuel cell. As fuel cell is an efficient device for its clean energy production. To enhance the efficiency of such type of clean energy devices an efficient electrode material is required for its proper working. In fuel cell, there is also a need to study the behavior of liquid fuel as well as their performance by using proper electrode material and catalyst. For this purpose to synthesize cathode material at nanoscale for SOFC to have high electrical conductivity and power density at low temperature. This approach is to prepare nanomaterial of the cathode for SOFCs that are low cost and operate efficiently at low temperature. A series of three samples of BaSrFeTi (BSFT) and three samples of LaSrFeTi (LSFT) nanomaterials for cathode has been fabricated and investigated. The variety of nanocompsite cathode materials were synthesized with different compositions by the Sol-Gel method, and sintered at 800 0C for four hours, and then grinded. These samples were characterized by XRD, EDX, SEM, and DC conductivity measurement. The prepared samples also shows at low temperature better electrical conductivities of BSFT is 0.13 Scm-1 at 650 0C and LSFT is 0.10 Scm-1 at 650 0C. The XRD results that both material Ba0.1 Sr0.1 Fe0.2 Ti0.6 (BSFT) and La0.1 Sr0.1 Fe0.2 Ti0.6 (LSFT) has a crystalline structure with three-phase(hexagonal, monoclinic, monoclinic), and their average crystalline size is 26.0 nm and BSFT has crystalline structure with tow-phase(hexagonal, monoclinic) their average crystalline size is 38.0 nm. The SEM results of samples represent that materials are homogenous and porous. The EDX analysis of samples successfully show their elemental composition and conformity.
Synthesis of Bismuth Doped Lanthanum Cobalt Iron Oxide Material as Cathode for Application of Solid Oxide Fuel Cell
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) ZOBIA ARIF; CIIT/SP20-RPH-027/LHR; Dr. Muhammad Ajmal Khan; LHR TP 7714
To reduce carbon dioxide emissions, which create global warming and climate change, the world is moving toward renewable energy sources. Solid oxide fuel cells are one of the most effective energy generation technologies due to their high energy conversion and low environmental impact. In this project, we are synthesized the bismuth doped lanthanum cobalt iron oxide cathode material. The proposed materials are bismuth doped lanthanum cobalt iron oxide (Bix (La0.5Co0.45 Fe0.05)1-x (BLCF)), where x=0.1, 0.2, 0.3 & 0.4 are prepared by sol gel technique. Different characteristics of cathode materials Bix (La0.5Co0.45Fe0.05)1-x are study in this project are X-ray diffraction (XRD), Raman spectroscopy, Fourier Transformation Infrared Spectroscopy (FTIR) and DC-conductivity by four probe methods. The Bi0.1 (La0.45Co0.405Fe0.045) XRD pattern shows that material has composite phase. The phase of Bismuth Iron oxide (average crystalline size 63.63 nm) has an orthorhombic structure (ICSD card No 96-900-8149), Bismuth Lanthanum Oxide (average crystalline size 50.65) has an orthorhombic crystal structure (ICSD card No 96-100-1472) and Lanthanum Cobalt Oxide (average crystalline size 26.42 nm) having orthorhombic crystal structure (ICSD card No 96-200-2266). In Bi0.2 (La0.4Co0.36Fe0.04) XRD pattern Lanthanum Bismuth Oxide (ICSD card No 96-901-5834) and Bismuth Cobalt Iron Oxide (ICSD card No 96-433-6779) having hexagonal structure with crystalline size 93.4 and 76.1 nm. The 3 rd sample Bi0.3 (La0.35Co0.315Fe0.035) XRD pattern shows Bismuth Cobalt Iron oxide (ICSD card No 96- 433-6780), Lanthanum Cobalt Oxide (ICSD card No 96-200-2266) and Bismuth Lanthanum Oxide (ICSD card No 96-100-1471) having monoclinic, orthorhombic, orthorhombic structure with crystalline size 67.7, 65.8 and 76.3 nm. The XRD pattern of Bi0.4 (La0.3Co0.27Fe0.03) shows that Bismuth Lanthanum Oxide (ICSD card No 96-100-1471), Bismuth Iron Oxide (ICSD card No 96-900-8149) and Cobalt Oxide (ICSD card No 96-900- 5888) have orthorhombic, orthorhombic and cubic with crystalline size 56.2, 61.3 and 91.8 respectively. Raman spectra of all samples [Bi (LCF)] show prominent bands at 128, 281, 320, 374, 486, 595, 621, 645 and 980 cm -1 related to La sit vibration, Fe-O vibration, O-B-O O, CoFeO, Co- O, Ag symmetry, stretching vibrations and Ag and Bg normal modes. FTIR spectra of all xi samples [Bi (LCF)] show the peaks at 1060, 1098, 1117, 1426 and 3500 to 3800 cm -1 having different modes and bond (stretching of C-C, Bi O-H, Co precipitation O= C = O stretching vibrations and vibrational peaks). We use DC four-probe methods to measure conductivity of material at different temperature (300-600) ℃. The sample Bi0.4 (La0.3Co0.27Fe0.03) shows the maximum conductivity (6.9 S/cm) at temperature 650 °C. We use EIS techniques to find the ORR of cathode material at (350 to 650 ℃) in air atmosphere. The sample Bi0.4 (La0.3Co0.27Fe0.03) shows the maximum ORR and good electronic behavior.
The Praseodymium Oxide/Strontium Oxide-based Proton Conductor as an Electrolyte for Solid Oxide Electrolyzer Cell
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Shoaib Ajmal; CIIT/SP21-RPH-030/LHR; Dr. Muhammad Ajmal Khan; LHR TP 8171
Clean energy is becoming more necessary nowadays because conventional energy re sources used for energy production are generating toxic gases, which cause environ mental pollution and increase global warming. Renewable energy sources are prefera ble in order to prevent these ecological issues. Therefore, hydrogen-based energy is a very emerging area nowadays. Hydrogen can be extracted from several sources, but high-temperature-based electrolyzer have gained prominence due to their low cost and terrific efficiency. In this project, composite proton conductor based solid oxide elec trolyzer Cell (SOEC) of Praseodymium PrxBa1-xMnO (X=0.1,0.2,0.3) and Strontium SrxBa1-xMnO (X=0.1,0.2,0.3) developed by solid state reaction (SSR) technique. Elec trochemical impedance spectroscopy (EIS) is used to examine their polarization losses, ohmic losses, and oxygen reduction reaction (ORR) mechanism in the temperature range of (550-650) oC. The FTIR study showed that the material has no nitrogen bond ing peak and that all nitrates evaporated during the sintering process. Weak O-H bonds indicate water in the material and produce H+ during ORR. In Raman spectroscopy the red shift in peaks has been observed. UV-Visible analysis found that Sr0.1Ba0.9MnO and Pr0.1Ba0.9MnO possess the maximum and Sr0.3Ba0.7MnO and Pr0.3Ba0.7MnO have the minimum band gaps of 1.5 eV and 1.7 eV respectively. The conductivity of Pr0.3Ba0.7MnO and Sr0.3Ba0.7MnO show maximum behaviors and having the values 10.1 mScm-1 and 9.2 mScm-1, respectively at 650 oC. As a result of their enhanced electrical conductivity and current density performance, the electrolyte materials produced for SOEC applications are promising contenders.