Department of Physics

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Author: search.filters.author.Dr. Ghazanfar AbbasSubject: search.filters.subject.Electrochemical

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    Investigation of the Electrochemical Effect of Rare Earth Materials on Zinc based Anode for SOFC
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) ATIF HAYAT; CIIT/FA20-RPH-043/LHR; Dr. Ghazanfar Abbas; LHR TP 7999
    Current scenario of the energy requirements motivates to researchers to explore the renewable energy resources. This also will be helpful to control the climate environmental issues to save the future. Fuel cells have aroused a lot of interest in this activity because of their high conversion efficiency when compared to traditional energy conversion approaches. Because of its low hazardous emissions, pollution, fuel adaptability, and cost-effective components, SOFCs are importance source for energy conversion technologies. Some issues are still need to be addressed, as conventional SOFC works at high temperature but the fact is that the SOFC activity reduces at low temperatures due to interfacial polarization blockages and the oxygen reduction process. In this context, in the present study zinc- based anode materials with composition Ce0.2(Zn0.5 Ni0.5)0.8, Sm0.2(Zn0.5 Ni0.5)0.8, Gd0.2(Zn0.5 Ni0.5)0.8 were synthesized via cost effective sol-gel technique. The effect of rare-earth materials has been investigated in terms of electrochemical properties. Their investigations consist of various characterizations such as Fourier Transformation Infrared Spectroscopy (FTIR), Raman Spectroscopy, UV-Vis, EIS, and fuel cell performance. FTIR is employed to analyse the chemical composition and its bounding. The FTIR spectrum the band at 1082 cm-1 can be attributed to the O- Ce-O stretching mode of vibration. The FTIR spectrum of zinc oxide nanoparticles absorbs at 648.50 cm−1. The absorption bands in the range of 743 cm−1 correspond to Ni-O stretching vibration mode. The large broad band at 3415cm-1 is ascribe to the O-H stretching vibration in OH groups. Raman spectroscopy is used to detect vibrational, rotational, and other states in a molecular system, capable of probing the chemical composition of materials. The Ce0.2(Zn0.5 Ni0.5)0.8 Raman pattern that the peak at 450-460 cm-1 attributed to Raman-active F2g mode of fluorite-structured CeO2. The Electrochemical properties were investigated by AC Electrochemical Impedance Spectroscopy (EIS) technique by 4-probe method under hydrogen atmosphere. The materials show the increasing behavior of conductivity with increasing the operating temperature. UV-visible characterization technique held to examine the optical properties of the sample and used to get the absorbance and reflectance spectra under the selected UV range of 190-800 nm. The fuel cell performance was carried out by making three –layers cell and maximum OCV was obtained 0.53V of Ce(NiZn) material.
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    Tuning the Catalyst Materials in Anode to Improve the Electrochemical Properties of Low Temperature Solid Oxide Fuel Cell
    (LHR TP 7695, 2021) Omer Abbas; CIIT/SP20-RPH-047/LHR; Dr. Ghazanfar Abbas; LHR TP 7695
    In present study zinc-based anode materials with composition Ba0.10Cu0.20M0.10Zn0.60 oxide (where M represent Mn, Mo, and Ag) were synthesized via cost effective sol-gel technique. The effect of suggested M components was observed to understand the electronic conduction mechanism with the diffusion of the hydrogen ion. In this work, materials synthesized by sol-gel technique and their functionalities are investigated as an anodic function of solid oxide fuel cell (SOFC). Their investigations consist of various characterizations such as Fourier Transformation Infrared Spectroscopy (FTIR), Raman Spectroscopy, X-ray diffraction (XRD) and Electrochemical Impedance Spectroscopy. FTIR technique is employed to analyse the chemical composition and its bounding. The Ba0.1Cu0.2Ag0.1Zn0.6O show that the peaks at 667 cm-1 738 cm- 1, 1121 cm-1, 1331 cm-1, 1664 cm-1, and 3238 cm-1 belong to Zn-O vibrational energy bond, the vibrational bond of C-O (symmetric) of ZnO, Zn-O stretching bonds and O-H hydroxyl group, respectively. The Ba0.1Cu0.2Mo0.1Zn0.6O show that the peaks at 675 cm-1 762 and 1339 cm-1, 1042 cm-1, 1121 cm-1, and 3010 cm-1are associated with the O-H bond, C-O bond, and C-H group, respectively. The Ba0.1Cu0.2Mn0.1Zn0.6O show that the peaks at 667 cm-1 754 cm-1, 875 cm-1, 1323 cm-1, 1113 cm-1, and 3644 cm-1 belong to Mn-O stretching bond, Zn-O vibrational energy, Zn-O bond, Zn-N bound bond, and O-H hydroxyl group, respectively. Raman spectroscopy is used to detect vibrational, rotational, and other states in a molecular system, capable of probing the chemical composition of materials. The Ba0.1Cu0.2Ag0.1Zn0.6O Raman pattern that the peak at 431 cm-1 belong to E2 High-E2 LOW mode of Zn-O, at 135 cm-1 peak associate to E2 High mode of Cu-O, and at 577 cm-1 relate to Cu-O, at 1144.54 cm-1 and peaks 1071 cm-1 related to AgO, and 1144 cm-1 linked to multi-phonon scattering process. The The Ba0.1Cu0.2Mo0.1Zn0.6O Raman pattern that the peaks observed at 135 cm- 1, 325.76 cm-1 for Cu-O and MoO, 577.18 cm-1 belongs to Cu-O, Zn-O at 435.3 cm-1 and 792.4, 837.4,8.889 and 1149 cm-1 relate to Mo-O bond. While, at 1149 cm-1 peak associate to the glass substrate. The Ba0.1Cu0.2Mn0.1Zn0.6O Raman pattern that the peaks at 337 cm- 1, 432 cm-1 belong to Zn-O mode of E2 high-E2 low, and E2 high, respectively. A peak at 659 cm- 1 belongs to the Mn-O group. While, at 964 cm-1 peak associate to the glass substrate, but at 1164 cm-1 is C-H group. X-ray diffraction used to calculate the crystal phase, cell parameter, volume, and density of a material. The Ba0.1Cu0.2Ag0.1Zn0.6O XRD pattern describes that oxide materials have composite nature consist of three-phase structures, where the phase of Zn-oxide (hexagonal structure, JCPDF 01-079-2205) may be in-cooperated with the phase of BaAg6O4 (orthorhombic structure, JCPDF 01-71-0749) and Cu-oxide (monoclinic structure, JCPDF 00-048-1548). The average crystallites sizes were found to be 85.2 nm, 96 nm, and 63.67 nm, respectively. The XRD pattern of Ba0.1Cu0.2Mo0.1Zn0.6O describes that oxide materials have composite nature consist of three-phase structures, the Cu-oxide (monoclinic structure, JCPDF 00-048-1548), BaMoO4 phase (tetragonal structure, JCPDF 00-008-0455), and Zn-oxide (hexagonal structure, JCPDF 01-079- 2205). The average crystallites sizes were found to be 78.45 nm, 65.63 nm, and 85.46 nm, respectively. The XRD pattern of Ba0.1Cu0.2Mo0.1Zn0.6O revealed that oxide materials have a three-phase structure, Zn-oxide (hexagonal structure, JCPDF 01-079-2205) is maybe in-cooperated with the phase of BaMn8O16 (tetragonal, JCPDF 00-029-0188) and Cu-oxide (monoclinic structure, JCPDF 00-048-1548). The average crystallites sizes were found to be 71 nm, 64 nm, and 57.6 nm, respectively. The Electrochemical properties were investigated by AC Electrochemical Impedance Spectroscopy (EIS) technique by 4-probe method under air and hydrogen atmosphere. The materials show the increasing behavior, with enhancing the temperature, which describes the nature of semiconductors and performance work of SOFC is under process
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    To investigate the Effect of Alkaline Earth Metals on Electrochemical Activities of Lanthanum Cobalt Zinc Oxide Cathode Materials
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) AQIB RAFIQUE NOORI; CIIT/SP20-RPH-024/LHR; Dr. Ghazanfar Abbas; LHR TP 7966
    In the modern age of science and technology every system of manual work is transferring to machines and to run these machines energy is required, so the need of time is motivating researchers to enhance their activities in the scope 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, lanthanam-based cobalt Zinc oxide cathode materials are prepared by sol-gel route alongwith the characterizions for the cathode functioning of solid oxide fuel cell (SOFC). FTIR technique is employed to analyse the chemical composition and its bounding. In BaLaCoZn peaks are found at 853 cm -1 ,859 cm -1 and 1426 cm -1 which are corresponding to C-O, La-O and Co-O respectively. In CaLaCoZn peaks are found at 703 cm -1 , 988 cm -1 , 1433 cm -1 which are attributed to Zn-O, C-O,Co-O, respectively. In SrLaCoZn peaks are observed at 856 cm -1 , 950 and 1441 cm -1 which belong to Sr-O, Zn-O respectively. For Sr1Co0.8La0.2 (SCL) peaks are found at 157 cm -1 , 525 cm -1 , 957 cm -1 and 1363 cm -1 . The analysis of existence of each and every C-H, C-C, C=C, O-H either of bending or stretching nature is given in following table against each wave number in each sample. In infrared spectroscopy, there are basically two regions, fingerprint region and functional groups region. The range of fingerprint region is from 400 cm -1 to 1500 cm -1 wave number which is not analyzed usually due to its complexity, as a large number of peaks appears in that region. Each bond represents existence of a functional groups. The prepared cathodes have 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. Raman spectroscopy is used to detect vibrational, rotational, and other states in a molecular system, capable of probing the chemical composition of materials. For samples BLCZ (S1) peaks are found at 157, 525, 957 and 1363 cm -1 . The peaks at 157 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 samples SLCZ (S3) peaks are found at 141, 296,649, 939, 1086 and 1344 cm -1 . The peaks at 141, 296 and 649 cm −1 wavelengths are analogous to O-B-O typical vibrations. The peaks at 939 and 1086 cm −1 wavelength correspond to B-O bonds stretching vibrations. Furthermore, for the Raman spectra of single Perovskite LSCF there is no mode vibrations in the range of 200–500 and 700–900 cm −1 can be found except (S2), which are xi demonstrative of double Perovskite structures LSCF materials. Therefore, the outcomes of the Raman spectral study agree well with those of literature, which showed that both the rhombohedra structure and double Perovskite phase are from space group R3C. So S1, S2 and S3 will behaves as an excellent cathode material as generating more oxygen ion vacancies which enhance the oxygen reduction reaction (ORR) at the cathode side. The electrical DC conductivity of prepared cathodes BaLaCoZn, CaLaCoZn and SrLaCoZn were measured by two probe method in the temperature range of (300-600) o C in the presence of methane as a fuel in air environment. The synthesized cathode material (S1) has maximum conductivity of 10.12 Scm -1 at 600 °C and the synthesized cathode material (S2) has minimum value of 3.3 Scm -1 at 300 °C.