Yazar "Saeed, Maham" seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Nitrogen and sulfur-rich cobalt complex for hybrid supercapacitor applications(Elsevier, 2025) Saeed, Maham; Shah, Javed Hussain; Sharif, Shahzad; Shahbaz, Muhammad; Ullah, Ghulam; Shahzad, Ayesha; Sahin, Zarife SibelIn the quest for more effective and advanced energy storage devices, an integrated methodology combining both battery and supercapacitor hybrid features is being explored. In this regard, we have developed a cobalt-1,10-phenonthroline complex with 5-sulfoisopthalic acid in the lattice (Co-Phen@SIP) via sonication method. Structural properties were explored by Single-crystal XRD, Elemental analysis, TGA, FTIR, UV Visible and Fluorescence spectroscopy while detailed electrochemical study was carried out via CV, GCD and EIS. Three electrode setup revealed pseudocapacitive properties of Co-Phen@SIP with specific capacity of 157.6 Cg(-1) at 2 A g(-1). Battery-supercapacitor hybrid device showed energy density and power density of 13.03 Wh kg(-1) and 3309 W kg(-1) respectively. The device also exhibited remarkable columbic efficiency of 98.94 % even after 5000 GCD cycles. Theoretical approach based on Dunn's model and power law was also applied to check the capacitivediffusive contributions of three-electrode system and hybrid device. 1, 10-phenonthroline induces structural stability over long cyclability. The introduction of SIP in Co-complex caused charge transfer through pi center dot center dot center dot pi interactions providing porous and robust structure which aided in improved electric conductivity and ionic mobility. This multi-ligand chemistry with the redox active cobalt has achieved superior performance and reversibility in comparison to other traditional complexes. The idea came out to be an effective strategy for advanced hybrid supercapacitors.Öğe Solvothermal synthesis, crystal structure, thermal, magnetic properties and DFT computations of a Ytterbium(III) complex derived from pyridine-2,6-dicarboxylic acid(Elsevier, 2022) Sharif, Shahzad; Saeed, Maham; Dege, Necmi; Bano, Rehana; Ahmad, Saeed; Gilani, Mazhar Amjad; Sahin, OnurA new ytterbium(III) complex, (DMAH(2))(3)[Yb(Pydc)(3)].4H(2)O (1) {Pydc = Pyridine-2,6-dicarboxylate anion, DMAH(2) = Dimethylammonium} has been prepared under mild solvothermal conditions and character-ized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. The DMAH2 molecules in 1 , generated in situ from hydrolysis of N,N-dimethylformamide are responsible to assemble 2D coordination polymer through N-H center dot center dot center dot O and O-H center dot center dot center dot O h ydrogen bonding. Magnetic suscepti-bility measurements indicate that the complex ( 1 ) obeys the Curie Weiss law and the overall magnetic behavior is typical for the presence of weak antiferromagnetic exchange coupling interactions. Theoretical data for geometrical parameters of complex 1 agree well with the experimental data. Large HOMO-LUMO energy gap of 4.33 eV has provided kinetic stability to the complex 1 . NBO analysis reflects that in-tramolecular charge transfer occurred between ligand and metal orbitals with the highest stabilization energy of 1024.04 kcal/mol. The negative electrostatic potential at the nitrogen and dianionic pyridine-2,6-dicarboxylate regions confirms that these are dynamic locations for Yb(III) binding. (c) 2022 Elsevier B.V. All rights reserved.Öğe Synergetic interplay of a nitrogen- and sulfur-rich copper bi-linker 2D cubic-layered MOF composite with MXene for improved hybrid supercapacitor application(Royal Soc Chemistry, 2025) Saeed, Maham; Sharif, Shahzad; Shah, Javed Hussain; Afzal, Tayyaba Tur Rehman; Shahbaz, Muhammad; Shehzad, Azhar Mehmood; Shahzad, AyeshaTo combine the properties of batteries and capacitors in a single hybrid device, metal-organic frameworks have emerged as promising materials. In this study, by incorporation of a heteroatom (N, O and S)-based bi-linker, a novel copper-based two-dimensional metal-organic framework (Cu-SIP-MOF), derived from 5-sulfoisophathalic acid monosodium salt (SIP sodium salt) and 4,4-bipyridine was synthesized and characterized using different techniques. The conductivity of the extended 2D MOF was attributed to pi-d orbital contribution, which was further enhanced by fabricating its composite with MXene. The synthesized MOFs and its composites were electrochemically evaluated using different electroanalytical techniques such as cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy via three-electrode assembly. The composites of Cu-SIP-MOF with MXene (CM-200) in a 1 : 2 ratio possessed the highest specific capacity of 683.69 C g-1, highlighting the potential for their practical implementation in asymmetric hybrid devices. The material demonstrated an energy density and a power density of 62 W h kg-1 and 2330.4 W kg-1, respectively. It also expressed 98.3% coulombic efficiency after 5000 galvanic charge-discharge cycles. The significant values of specific capacity, energy density and power density of CM-200 make it a promising electrode material for a futuristic hybrid device.Öğe Synergistic interplay of 1D bimetal Co-Ni-MOF@rGO for hybrid energy storage device(Elsevier Science Sa, 2025) Saeed, Maham; Sharif, Shahzad; Razia, Eesha Tur; Shahzad, Ayesha; Raza, Muhammad Arshad; Arshad, Beenash; Afaq, QararAs current era research ignites the focus towards finding better electrode material for renewable energy devices so, a cobalt and nickel-based bimetallic metal organic framework derived from 1,2,4,5-benzenetetracarboxylic acid was synthesized and characterized by Single crystal X-ray diffraction, Powder X-Ray diffraction, SEM, BET, elemental analysis, FTIR and TGA. Owing to pseudocapacitve properties of Co-Ni-MOF due to 1D pi-d conjugated layers, reduced graphene oxide (rGO) in different ratios was used to improve its conductivity and the fabricated composites were examined in three electrode system. Excess amount of rGO can overly occupy the MOF structure reducing redox active sites and electrochemical performance. CoNi@rGO2 appeared as the best optimized sample with highest specific capacity, specific capacitance of 567.40C/g and 1260.8 F/g at 1 A/g respectively. For the practical viability, it was integrated into a hybrid device which delivered specific capacity of 319.21C/g, an energy density of 64.29 Wh/kg, power density of 5346.21 W/kg and 98.3 % columbic efficiency after 7000 cycles. CoNi@rGO2//AC appeared as an exceptional hybrid energy device with practical and financial worth paving the way to develop similar materials for futuristic energy storage applications.Öğe Tuning the electrochemical performance of a copper-based 2D rectangular layered metal organic framework by incorporating reduced graphene oxide and polyaniline(Royal Soc Chemistry, 2026) Riasat, Madiha; Shahbaz, Muhammad; Ullah, Ghulam; Mushtaq, Muhammad Waheed; Saeed, Maham; Shahzad, Sundas; Shahzad, AyeshaTo meet the challenge of developing efficient energy storage devices, metal organic frameworks (MOFs) with intrinsic properties have emerged as promising candidates. The conductivity and stability of the extended 1D pi-d and pi-pi stacking in a 2D MOF can be further enhanced by fabricating its composite with conductive materials. Herein, a nitrogen-containing 2D Cu-PDA MOF was synthesized and mixed with conductive materials, such as reduced graphene oxide (rGO) and polyaniline (PANI), to enhance the electrical conductivity. After structural investigation, the electrochemical attributes of Cu-PDA and its composites (Cu-PDA@rGO and Cu-PDA@PANI) have been explored by utilizing different electroanalytical techniques like CV, GCD and EIS analyses. In a three-electrode assembly, Cu-PDA@rGO shows a specific capacity of 551.31 C g-1. Hence, for practical applications, a hybrid supercapacitor has been designed by fabricating Cu-PDA@rGO against activated carbon (AC), which reveals a specific capacity of 159.4 C g-1, a specific energy of 32.10 Wh kg-1 and a specific power of 180.17 W kg-1 while maintaining a coulombic efficiency of 99.4% even after 5000 GCD cycles. These excellent findings demonstrate that Cu-PDA@rGO is a potential candidate for future energy storage devices.
