GHAZANFAR ABBAS | National University of Science and Technology (original) (raw)

Papers by GHAZANFAR ABBAS

International Journal of Energy Research

Journal of Electrochemical Energy Conversion and Storage, 2020

The world’s present reserves in terms of fossil fuels are exhausting speedily. Such rapid energy ... more The world’s present reserves in terms of fossil fuels are exhausting speedily. Such rapid energy consumption can be caused of unsustainable worldwide progress. Therefore, the researcher’s challenge is to identify the most efficient and economical energy conversion method to provide a viable replacement for the ongoing conventional energy converters. In this context, fuel cell technology (solid oxide fuel cells (SOFCs)) can play a key role and convert hydrocarbon energy into electrical energy. The conventional electrolyte YSZ based SOFCs work at high temperature ∼1000 °C. In this present research, the new ceramics electrolytes materials boron doped ceria (BDC) have been developed by auto-combustion technique. The prepared materials have been characterized by X-ray diffraction (XRD) and TEM. The crystallite sizes of all prepared samples are in the range of 50–80 nm applying Scherer’s formula. The electrical studies and fuel cell performance have been completed at temperature ≤ 700 °C....

Advances in Nanostructured Composites, 2019

Ceramics International, 2020

Abstract The cobalt containing cathode is always challenging because of high cost, reduction of c... more Abstract The cobalt containing cathode is always challenging because of high cost, reduction of cobalt and high thermal expansion for SOFC. Therefore, cobalt-free perovskite oxides nanostructure cathodes LaxSr1-xFe1-yCuy O3-δ (x = 0.54, 0.8, y = 0.2, 0.4) are synthesized by sol-gel method in this paper. The microstructure, electrical and transport properties of prepared nanomaterials were studied. The characterizations of synthesized materials are performed by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The thermal effects are monitored by using Thermogravimetric analysis (TGA). The electrochemical studies of prepared cathodes are accomplished with four-probe DC method. The conductivities of La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ are achieved as 6.007, 3.042 and 2.002 Scm−1, respectively at 500 °C but maximum conductivities of La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ are obtained as 9.029, 6.237 and 5.266 Scm−1, respectively at 600 °C. The power densities are noted as 267, 201 and 156 mWcm−2 for La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ, respectively at 500 °C. The peak power densities are recorded as 452, 366 and 270 mWcm−2 for La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ, respectively at 600 °C. The current densities as 1251 mAcm−2, 1179 mAcm−2 and 1107 mAcm−2 for La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ are obtained, respectively at 500 °C. The significant current densities as1480 mAcm−2, 1420 mAcm−2 and 1370 mAcm−2 for La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ are achieved, respectively at 600 °C. The XRD data revealed the perovskite phase while results of SEM indicate that materials were homogeneous. The prepared La0.54Sr0.46Fe0.80Cu0.20O3-δ, La0.80 Sr0.20 Fe0.80Cu0.20 O3-δ and La0.80 Sr0.20 Fe0.60Cu0.40 O3-δ cathodes have maximum open circuit voltage 0.918,0.86 and 0.82 V at 600 °C.

Journal of The Electrochemical Society, 2020

Ceramics International, 2019

These resources also are polluting the climate rapidly. With reference to these alarming situatio... more These resources also are polluting the climate rapidly. With reference to these alarming situations, solid oxide fuel cells have got great attention in the field of energy conversion technologies due to their low emissions, fuel flexibility and higher efficiency characteristics. In the present investigation, two anode materials with compositions Al 0.1 Mn 0.1 Zn 0.8 O (AMZ) and Al 0.1 Mn 0.1 Ni 0.1 Zn 0.7 O (AMNZ) were prepared via solid state reaction. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were accomplished to investigate the phase and surface morphology study of synthesized materials. The crystallite sizes of the prepared materials have been assessed using Scherer's formula and found to be 52 and 61 nm for AMZ and AMNZ, respectively. The conductivities of AMZ and AMNZ were obtained 4.4 and 5.2 S/cm, respectively at 650°C. The activation energy was calculated by drawing Arrhenius plots. The prepared materials showed both ionic and electronic conduction behaviour as confirmed by electrochemical impedance measurements. The AMNZ composition has higher value of open circuit voltage (1.01 V) and power density (535 mW/cm 2) in hydrogen atmosphere as compared with AMZ at 550°C, which indicates that Ni contents in anode improvs the properties and can be considered as promising anode material at low temperature for fuel cell applications.

Journal of Power Sources, 2019

Multi-fuel based NBCZ oxide anode was successively synthesized by solgel method. • The crystallit... more Multi-fuel based NBCZ oxide anode was successively synthesized by solgel method. • The crystallite size of NBCZ material was found 25-90 nm by XRD and SEM analysis. • The power density was found between 57-315 mW cm −2 at 600°C among different fuels.

Journal of Electronic Materials, 2018

A facile and simple synthetic route has been employed to synthesize rodshaped optically efficient... more A facile and simple synthetic route has been employed to synthesize rodshaped optically efficient cadmium sulfide (CdS) mesoscopic structures using high concentrations of cetyl trimethyl ammonium bromide (CTAB) as the stabilizing agent. The mesoscopic structures were characterized using x-ray diffaractometer (XRD), scanning electron microscopy, UV-visible, photoluminescence (PL), and Fourier transform and infrared (FTIR) spectroscopy. It was found that, if the concentration of CTAB is significantly higher than its critical micelle concentration, the nucleation of CdS mesoscopic structures resulted in rod-like structures. The size of the mesoscopic structures initially increased and then decreased with band gaps 2.5-2.7 eV. XRD analysis showed that the samples had a pure cubic phase confirming the particle size. The values of Urbach energy for the absorption tail states were determined and found to be in agreement with the single crystal. PL spectra showed sharp green emission peaks in the 530-nm to 560-nm wavelength range. FTIR spectra showed the adsorption mode of CTAB onto the CdS mesoscopic structures. A possible mechanism of formation of rod-shaped CdS mesoscopic structures is also elucidated.

Journal of Materials Science: Materials in Electronics, 2017

Conducting polymers and their composites are receiving considerable attention due to their applic... more Conducting polymers and their composites are receiving considerable attention due to their applications in commercial and domestic appliances based on their electrical, optical and thermal properties. Also the magnetic and conducting properties of ferrite/polypyrrole (PPy) composites have opened a new horizon in multifunctional materials. In the present study, different properties of PPy, holmium substituted ferrite and their composites have been investigated. Prior to that, PPy was prepared by the chemical polymerization method of pyrrole in the presence of FeCl 3 ⋅6H 2 O. Holmium substituted ferrite Co 0.02 Ho 1.98 Fe 2 O 4 was prepared by using co-precipitation technique. The X-ray diffraction (XRD) pattern showed crystalline ferrite phase having an average crystallite size of 27 nm. Composites with different ratios of ferrite and PPy were fabricated using solid state reaction technique. The structural and morphological properties of PPy/Ferrite composites were studied by XRD and scanning electron microscopy (SEM), respectively. Frequency dependent dielectric properties were studied in the range of 1 MHz-3 GHz; the dielectric constant value for composite is higher than that for the holmium ferrite. The higher dielectric constant of the composite indicates that these materials have better ability to store potential energy under the influence of alternating electric field.

Journal of Alloys and Compounds, 2019

In recent scientific research, an interest has been gained significantly by rare earth metals suc... more In recent scientific research, an interest has been gained significantly by rare earth metals such as cerium (Ce), samarium (Sm) and gadolinium (Gd) due to their use in fuel cells as electrolyte and catalysts. When used in an electrolyte, these materials lower the fuel cell's operating temperature compared to a conventional electrolyte, for example, yittria-stablized zirconia (YSZ) which operates at a high temperature (≥800 o C). In this paper, the tri-doped ceria, M 0.2 Ce 0.8 O 2-δ (M=Sm 0.1, Ca 0.05, Gd 0.05) electrolyte powders was synthesized using the co-precipitation method at 80 o C. These dopants were used for CeO 2 with a total molar ratio of 1M. Dry-pressed powder technique was used to make fuel cell pellets from the powder and placed them in the furnace to sinter at 700 o C for 60 minutes. Electrical conductivity of such a pellet in air was 1.2 × 10-2 S.cm-1 at 700 o C measured by the ProboStat-NorECs setup. The crystal structure was determined with the help of-ray diffraction (XRD), which showed that all the dopants were successfully doped in CeO 2. Raman spectroscopy and UV-VIS spectroscopy were also carried out to analyse the molecular vibrations and absorbance, respectively. The maximum open-circuit voltages (OCVs) for hydrogen and ethanol fuelled at 550 ˚C were observed to be 0.89 V and 0.71 V with power densities 314 mW.cm-2 and 52.8 mW.cm-2 , respectively.

ACS applied materials & interfaces, Jan 19, 2017

Samarium doped ceria-carbonate(SDC) has become an attractive electrolyte for low temperature fuel... more Samarium doped ceria-carbonate(SDC) has become an attractive electrolyte for low temperature fuel cells because of its impressive ionic conductivity and high performance. Different doped ceria-carbonate (SDC-single, SDC-binary, and SDC-ternary) electrolytes were synthesized by the co-precipitation/oxalate method, to optimize the electrochemical performance. The structure, morphology, and thermal, optical, and surface properties, have been studied using a variety of techniques. These include x-ray diffraction, scanning electron microscopy, thermogravimetric analysis, UV-visible absorption spectroscopy, and Fourier infrared spectroscopy. The x-ray diffraction results confirmed the successful incorporation of samarium into ceria as a crystalline and inclusion of carbonate is an amorphous nature. To analyze the conduction mechanism, dc conductivity was measured in a H2/O2 atmosphere. Doped ceria-binary carbonate (Li/Na)CO3-SDC) showed the highest ionic conductivity of 0.31 S cm-1, and p...

International Journal of Modern Physics B, 2017

Zinc-based nanostructured nickel (Ni) free metal oxide electrode material Zn[Formula: see text]/C... more Zinc-based nanostructured nickel (Ni) free metal oxide electrode material Zn[Formula: see text]/Cu[Formula: see text]Mn[Formula: see text] oxide (CMZO) was synthesized by solid state reaction and investigated for low temperature solid oxide fuel cell (LTSOFC) applications. The crystal structure and surface morphology of the synthesized electrode material were examined by XRD and SEM techniques respectively. The particle size of ZnO phase estimated by Scherer’s equation was 31.50 nm. The maximum electrical conductivity was found to be 12.567 S/cm and 5.846 S/cm in hydrogen and air atmosphere, respectively at 600[Formula: see text]C. The activation energy of the CMZO material was also calculated from the DC conductivity data using Arrhenius plots and it was found to be 0.060 and 0.075 eV in hydrogen and air atmosphere, respectively. The CMZO electrode-based fuel cell was tested using carbonated samarium doped ceria composite (NSDC) electrolyte. The three layers 13 mm in diameter and 1...

International Journal of Modern Physics B, 2016

Fuel cell is undoubtedly widespread energy conversion technology, which can convert fuel (biogas)... more Fuel cell is undoubtedly widespread energy conversion technology, which can convert fuel (biogas) energy into electricity. Solid oxide fuel cell (SOFC) is one of the best choices among the fuel cell’s family due to high efficiency and fuel flexibility. In this study, zinc-based nanostructured [Formula: see text] electrode materials were successfully developed by solid state reaction. The proposed materials have been characterized by XRD and SEM. The electrical conductivities have been examined by four-probe DC method in the temperature range of 300–600[Formula: see text]C, the maximum values were recorded and found to be 12.019 and 5.106 S/cm at natural gas and air atmosphere, respectively. The electrochemical performance has been measured employing NK-SDC electrolyte material and their current density versus voltage and current density versus power density (I-V and I-P characteristics) have been drawn. The maximum power density was found to be 170 mW/cm2 using natural gas as a bio-...

Applied Physics Letters, 2015

Applied Surface Science, 2015

Abstract The surface of ultra-high molecular weight polyethylene (UHMWPE) powder was functionaliz... more Abstract The surface of ultra-high molecular weight polyethylene (UHMWPE) powder was functionalized with styrene using chemical grafting technique. The grafting process was initiated through radical generation on base polymer matrix in the solid state by sodium thiosulfate, while peroxides formed at radical sites during this process were dissociated by ceric ammonium nitrate. Various factors were optimized and reasonably high level of monomer grafting was achieved, i.e., 15.6%. The effect of different acids as additive and divinyl benzene (DVB) as a cross-linking agent was also studied. Post-grafting sulfonation was conducted to introduce the ionic moieties to the grafted polymer. Ion-exchange capacity (IEC) was measured experimentally and is found to be 1.04 meq g −1 , which is in close agreement with the theoretical IEC values. The chemical structure of grafted and functionalized polymer was characterized by attenuated total reflection infrared spectroscopy (ATR-FTIR) and thermal properties were investigated by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal analysis depicts that the presence of radicals on the polymer chain accelerates the thermal decomposition process. The results signify that the chemical grafting is an effective tool for substantial surface modification and subsequent functionalization of polyethylene.

Nanoscience and Nanotechnology Letters, 2012

Composite electrodes of Cu 0 16 Ni 0 27 Zn 0 37 Ce 0 16 Gd 0 04 (CNZGC) oxides have been successf... more Composite electrodes of Cu 0 16 Ni 0 27 Zn 0 37 Ce 0 16 Gd 0 04 (CNZGC) oxides have been successfully synthesized by solid state reaction method as anode material for low temperature solid oxide fuel cell (LTSOFC). These electrodes are characterized by XRD followed by sintering at various time periods and temperatures. Particle size of optimized composition was calculated 40-85 nm and sintered at 800 C for 4 hours. Electrical conductivity of 4.14 S/cm was obtained at a temperature of 550 C by the 4-prob DC method. The activation energy was calculated 4 × 10 −2 eV at 550 C. Hydrogen was used as fuel and air as oxidant at anode and cathode sides respectively. I-V/I-P curves were obtained in the temperature range of 400-550 C. The maximum power density was achieved for 570 mW/cm 2 at 550 C.

ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 1, 2010

An oxide based two phase nanocomposite electrolyte (Ce0.9Gd0.1O2) was synthesized by a co-precipi... more An oxide based two phase nanocomposite electrolyte (Ce0.9Gd0.1O2) was synthesized by a co-precipitation method and coated with Yttrium oxide (Y2O3). The nanocomposite electrolyte showed the significant performance of power density 750mW/cm2 and higher conductivities at relatively low temperature 550°C. Ionic conductivities were measured with electrochemical impedance spectroscopy (EIS) and DC (4 probe method). The structural and morphological properties of the prepared electrolyte were investigated by means of High Resolution Scanning Electron Microscopy (HRSEM). The thermal stability was determined with Differential Scanning Calorimetry (DSC). The particle size was calculated with Scherrer formula and compare with SEM results, 15–20 nm is in a good agreement with the SEM and X-ray diffraction (XRD) results. The purpose of the study to introduce the functional nanocomposite materials, for advanced fuel cell technology (NANOCOFC) to meet the challenges of solid oxide fuel cell (SOFC).

Legal Medicine, 2015

The analysis of mitochondrial DNA (mtDNA) control region was carried in 85 unrelated Sariki indiv... more The analysis of mitochondrial DNA (mtDNA) control region was carried in 85 unrelated Sariki individuals living in the different provinces of Pakistan. DNA was extracted from blood preserved in EDTA vacutainers. Hypervariable regions (HV1, HV2 & HV3) were PCR amplified and sequenced. Sequencing results were aligned and compared with revised Cambridge reference sequence (rCRS). The sequencing results showed presence of total 63 different haplotypes, 58 of them are unique and 05 are common haplotypes shared by more than one individual. The most common haplotype observed was (W6) with a frequency 12.9% of population sample. The Saraiki population was detected with genetic diversity (0.9570) and power of discrimination (0.9458). This study will be beneficial for forensic casework.

Journal of Magnetism and Magnetic Materials, 2015

A series of single phase spinel ferrites having chemical formula Mg 0.5 Zn 0.5 Pr x Fe 2 À x O 4 ... more A series of single phase spinel ferrites having chemical formula Mg 0.5 Zn 0.5 Pr x Fe 2 À x O 4 (x ¼ 0.00, 0.05, 0.10, 0.15, 0.20, 0.25) were prepared using the sol-gel technique after sintering at 700°C. The thermal decomposition behavior of an as prepared powder was investigated by means of DTA/TGA analyses. The sintered powders were then characterized by Fourier transform infrared spectroscope, X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscope and vibrating sample magnetometer. X-ray diffraction patterns confirm the single phase spinel structure of prepared ferrites without the presence of any impurity phase. The value of lattice parameter (a) increases with the increase of Pr contents (x) into the spinel lattice. The grain size estimated from electron microscope images is in the range of 2.75-5.4 mm which confirms the spinel crystalline nature of the investigated samples. The saturation magnetization (M s) decreases whereas coercivity (H c) increases with the increase of Pr contents (x). The measured parameters suggest that these materials are favorable for high frequency applications and as core materials.

International Journal of Hydrogen Energy, 2015

Alkaline anion-exchange membranes (AAEMs) for solid alkaline fuel cells (SAFC) application were s... more Alkaline anion-exchange membranes (AAEMs) for solid alkaline fuel cells (SAFC) application were successfully prepared by radiation induced grafting of Vinyl benzyl chloride onto ultra-high molecular weight polyethylene powder (UHMWPE), followed by film fabrication by melt pressing and quaternization with a Guanidine derivative, 1,1,3,3-tetramethyl-2-nbutylguanidine (TMBG). The chemical structures of the resulting AAEMs were examined by Fourier transform infrared, which showed that the grafted membranes were successfully functionalized by modified guanidine. The performance of the AEMs, including ion exchange capacity, water uptake, in-plane swelling, methanol uptake, methanol permeability, and hydroxide ion conductivity were investigated. Thermal analysis showed that the Guanidine-based AAEMs comprises better thermal stability. The AAEMs membrane exhibited a maximum ionic conductivity of 27.7 mS cm À1 at 90 C. Methanol permeability is found to be in the order of 10 À9 cm 2 s À1 , which is significantly lower than that of Nafion ®. The membranes have useful properties as an anion exchange membranes suitable for alkaline fuel cells.