Yazar "Shahzad, Sundas" seçeneğine göre listele

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    Enhanced electrochemical performance of cerium-based metal organic frameworks derived from pyridine-2,4,6-tricarboxylic acid for energy storage devices
    (Elsevier, 2024) Shahbaz, Muhammad; Sharif, Shahzad; Shahzad, Ayesha; Sahin, Zarife Sibel; Riaz, Bilal; Shahzad, Sundas
    Modern era demands development of hybrid supercapacitor amalgamating characteristics of battery and supercapacitor is a single unit. Various contender electrode materials have been used so far, however, metal organic frameworks, having rich porosity and distinctive electrochemical properties can be integrated in energy storage devices to improve electrochemical performance. Herein, we have synthesized Ce-PTA-MOF from pyridine-2,4,6-tricarboxylic acid which was structurally as well as electrochemically characterized. Effects of different concentrations of KOH electrolyte on electrochemical properties of Ce-PTA-MOF electrode has been investigated using three electrodes assembly and practical applications of hybrid supercapacitor device has also been explored by fabricating it with activated carbon. The stability and capacitive-diffusive contributions of the hybrid supercapacitor has been analyzed by theoretical approach. The specific capacity, maximum energy density and power density were calculated as 115 C/g, 26.75 Wh/kg and 5760 W/kg respectively which showed efficiency of 99.2 % even after 5000 GCD cycles. High energy density and power density with extraordinary stability make Ce-PTA-MOF electrode a promising candidate for futuristic hybrid supercapacitor devices.
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    Pyridine-2,6-Dicarboxylic Acid As a Facile and Highly Selective Turn-Off Fluorimetric Chemosensor for Detection of Cu (II) Ions in Aqueous Media
    (Springer/Plenum Publishers, 2024) Shah, Javed Hussain; Sharif, Shahzad; Shahbaz, Muhammad; Riaz, Bilal; Shahzad, Sundas; Sahin, Onur; Munawar, Khurram Shahzad
    Copper metal is third most abundant trace element in human body. Determination of Cu (II) ions is a burning topic in field of environment protection and food safety because of its significant impact on ecosystem. In this study, 2,6-pyridine dicarboxylic acid (PDA) has been explored as turn-off florescent probe for florescent detection of Cu (II) ions. This sensor showed highly selective complexing ability towards Cu (II) ions. Addition of aqueous solution of Cu (II) ions remarkably quenched the fluorescence intensity of PDA while, on contrary, there was no any prominent fluorescence quenching interference on addition of various metal ions. The binding mode of PDA and Cu (II) ions was determined as stoichiometry of 1:1 and it was further confirmed by single crystal XRD analysis. Mechanisms of static and dynamic quenching were confirmed by stern-volmer plot. Limit of detection (LOD) and limit of quantification (LOQ) for Cu (II) ions was calculated as 3.6 mu M and 1.23 mu M respectively, which is far below the acceptable value (31.5 mu M) according to the World Health Organization. The use of the sensor for detection of Cu (II) ions in real samples in aqueous media was also performed.
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    Öğe
    Redox active cobalt based bi-linker metal organic frameworks derived from 5-sulfoisopthalic acid and 4,4-bipyridine for supercapacitor
    (Pergamon-Elsevier Science Ltd, 2025) Shah, Javed Hussain; Shahbaz, Muhammad; Sharif, Shahzad; Ullah, Ghulam; Shahzad, Sundas; Munawar, Khurram Shahzad; Sahin, Onur
    In this research study, we have synthesized, characterized and extensively compared the electrochemical characteristics of two materials derived from 5-sulphoisophtalic acid, 4,4-bipyridine and cobalt metal using sonochemical method. Cobalt-bipyridine complex with 5-SIP in lattice structure (RG-41) showed predominant capacitive behavior whereas Co-SIP-Bpy MOF (RG-42) exhibited significant pseudocapacitive attributes due to the presence of coordination linkage responsible for the electron transfer. Due to the effective electrochemical properties of RG-42, we implemented it practically by fabricating a hybrid device with outstanding electrochemical features, demonstrating impressive 92 % cyclic stability with energy density and power density of 51.41 Wh/kg and 800 W/kg at 1 A/g, respectively. Dunn's method was employed to obtain capacitive-diffusive contributions for both half-electrochemical cells as well as hybrid device. These results underscored the potential of RG-42 as a competitive electrode material for future energy storage applications.
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    Structural, DFT and redox activity investigation of 2D silver based MOF for energy storage devices
    (Elsevier Science Sa, 2024) Sharif, Shahzad; Shah, Javed Hussain; Shahbaz, Muhammad; Riaz, Bilal; Shahzad, Sundas; Shahzad, Ayesha; Sahin, Onur
    A new silver(I) 2D MOF (Ag -MOF) was synthesized from 3,4-pyridinedicarboxylic acid (PDCA) by sonication method and characterized by single crystal X-ray diffraction, elemental analysis and FTIR spectroscopy. The material was further utilized for DFT computation and electrochemical performance. Theoretical and practical results for Ag -MOF geometrical parameters were found to be in reasonable agreement. Small HOMO-LUMO energy distance of 0.47 eV confirmed that electron transfer was much feasible. Distribution of electron isodensities was elaborated by DFT and FMOs computation. Double redox peaks in CV voltammograms reflected the change in oxidation state. Multiple plateaus in GCD curves showed the pseudo-capacitive behavior. Ag -MOF exhibited 101 Cg -1 specific capacity (Q s ), 123 Wh.kg - 1 energy density and 12,960 W kg -1 power density at current density of 5 Ag -1 . There was a small difference in R ct and R i which revealed that Ag -MOF had great ability to store energy. Presence of semi-circular arc in the EIS spectrum directly dictates the supercapacitor behavior. The electrode showed 97.5 % cyclic stability after 5000 cycles.