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1,175 results on '"Ibrahim, Mohamed M."'

123. Poly(vinyl alcohol)/polyacrylamide double‐network ionic conductive hydrogel strain sensor with high sensitivity and high elongation at break.

Author

Wu, Zijian, Liu, Xiaorui, Xu, Qi, Zhang, Liying, Abdou, Safaa N., Ibrahim, Mohamed M., Zhang, Jing, El‐Bahy, Zeinhom M., Guo, Ning, Gao, Junguo, Weng, Ling, and Guo, Zhanhu

Subjects
STRAIN sensors, TENSILE strength, WEARABLE technology, HYDROGELS, BIOCOMPATIBILITY
Abstract

As a soft material with biocompatibility and stimulation response, ionic conductive hydrogel‐based wearable strain sensors show great potential across a wide spectrum of engineering disciplines, but their mechanical toughness is limited in practical applications. In this study, freeze‐thawing techniques were utilized to fabricate double‐network hydrogels of poly(vinyl alcohol)/polyacrylamide (PVA/PAM) with both covalent and physical cross‐linking networks. These double‐network hydrogels demonstrate excellent mechanical performance, with an elongation at break of 2253% and tensile strength of 268.2 kPa. Simultaneously, they also display a high sensitivity (Gage factor, GF = 2.32 at 0%–200% strain), achieve a rapid response time of 368 ms without the addition of extra conductive fillers or ions, stable signal transmission even after multiple cycles, and fast response to human motion detection. [ABSTRACT FROM AUTHOR]

Published
2024
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124. La+3-doped CoFe2O4@MXene bifunctional electrocatalyst for superior OER and HER activity.

Author

Yousaf, Sheraz, Abdou, Safaa N., Afaq, Muhammad, Ibrahim, Mohamed M., Shakir, Imran, El-Bahy, Salah M., Ahmad, Iqbal, Shahid, Muhammad, and Warsi, Muhammad Farooq

Abstract

The lanthanum doped cobalt ferrite (La+3-CoFe2O4) incorporated in MXene sheets bifunctional electrocatalyst was prepared and then subjected to various analyses to assess their structural, morphological, and functional group characteristics. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) were employed for this purpose. The electrochemical performance of La-CoFe2O4@MXene was investigated in an alkaline solution to assess the bifunctional (OER/HER) performances. The results revealed that La-CoFe2O4@MXene exhibited significantly lower overpotential and a lesser Tafel slope during OER compared to both CoFe2O4 and La-CoFe2O4 materials. Similarly, during HER, La-CoFe2O4@MXene demonstrated superior performance. The electrochemical impedance (EIS) analysis was also conducted on all samples. These results indicated that the La-CoFe2O4@MXene electrocatalyst displayed reduced charge transfer resistance (2.18 Ω) and a higher exchange current density (2.94 mA cm−2) compared to its counterparts. These results collectively demonstrate the exceptional electrocatalytic behavior of La-CoFe2O4@MXene. This enhanced performance is likely attributable to the synergistic effect of lanthanum doping, which introduces defects into the material, and the presence of MXene sheets, which facilitates faster charge transfer within the electrocatalyst. To the best of our knowledge, this is the first study to explore La-CoFe₂O₄@MXene for water splitting. Our results demonstrate that this material requires significantly lower overpotential for OER and HER in an alkaline medium, showcasing its potential as an efficient and cost-effective catalyst for water splitting. Highlights: MXene-based La+3-doped-CoFe2O4 electrocatalyst has been prepared for bifunctional electrocatalytic activity. The coprecipitation and ultrasonication methods were adopted for the synthesis of bifunctional electrocatalysts, which were responsible for enhanced electrochemical active surface area and superior OER/HER performance. The La-CoFe2O4@MXene exhibited an OER onset potential of 1.47 V versus RHE, while for HER it is 0.26 V versus RHE. The bifunctional material exhibited a 277 mV overpotential to attain 10 mA cm−2 current density during OER and a 285 mV overpotential to reach 100 mA cm−2 current density during HER performance. The excellent bifunctional performance is attributed to the presence of MXene sheets, which facilitates higher conductivity, a greater number of active sites, and superior charge transfer kinetics for the water splitting reactions. [ABSTRACT FROM AUTHOR]

Published
2024
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125. Impact of crystallite size of LiCu0.5Fe2-yCeyO4 nanospinel ferrites on opto-dielectric properties.

Author

Taleb, Manal F. Abou, Afzal, F., Hussain, Q., Ibrahim, Mohamed M., El-Bahy, Zeinhom M., and Rahman, A. U.

Subjects
DIELECTRIC measurements, DIELECTRIC loss, DIELECTRIC properties, ABSORPTION spectra, BAND gaps
Abstract

This study explores the impact of crystallite size on the opto-dielectric properties of LiCu0.5Fe2-yCeyO4 (y = 0.0, 0.01, 0.02, 0.03, 0.04) nanospinel ferrites (NSFs) synthesized via sol–gel auto-combustion. X-ray diffraction (XRD) analysis confirmed the crystalline nature and phase purity, revealing variations in crystallite size within the nanoscale range. Fourier-transform infrared spectroscopy (FTIR) provided insights into chemical bonding, affirming the composition and structure reliability. Morphological characterization via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the nanostructure, highlighting the influence of crystallite size on particle morphology, shape, and size distribution. Energy-dispersive X-ray spectroscopy (EDX) verified the presence of expected elements, with elemental composition offering spatial distribution insights. Inductively coupled plasma (ICP) analysis quantified elemental concentrations, focusing on Li, Cu, Fe, and Ce. Optical properties, including UV–vis absorption spectra, were measured to assess band gap energies. Dielectric measurements across a range of frequencies provided insights into the pure Li-Cu NSFs and Ce3+ doped Li-Cu NSFs dielectric response, revealing variations in dielectric constant and loss tangent with changing crystallite size. The findings highlighted the significant role of crystallite size in modulating both energy band gap and dielectric properties, essential for applications in high-frequency, photonics, electronics, and sensor technologies. [ABSTRACT FROM AUTHOR]

Published
2024
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150. Study of photoelectrochemical (PEC) solar cell properties of n-type bismuth sulfide (n-Bi2S3)/p-type copper (I) iodide (p-CuI) heterojunction synthesized by SILAR.

Author

Sonar, Shital M., Guo, Zhanhu, Ibrahim, Mohamed M., Mersal, Gaber A. M., Tarkas, Hemant S., and Ahirrao, Prakash B.

Abstract

Photoelectrochemical (PEC) solar cell properties of the synthesized n-type bismuth sulfide (n-Bi2S3)/p-type copper (I) iodide (p-CuI) heterojunction using an easy approach of successive layer adsorption and reaction have been studied. X-ray diffraction (XRD) was used to give an insight of the structures, morphological study was carried out in a scanning electron microscopy (SEM), and the band gap was studied in an ultraviolet–visible spectroscopy. Photoluminescence (PL) analysis was also carried out, and contact angle was measured to understand the interaction of film surface and liquid. Bi2S3 exhibits a zinc blende face-centered cubic (FCC) structure and CuI shows an orthorhombic phase, whereas the optical band gap of n-Bi2S3/p-CuI is found to be 2.84 eV. The surface for CuI crystallites shows a tetrahedral form, sharp edges, and a good substrate coating but interlocked nanoparticles with nanoporosity being discovered for Bi2S3. With increasing SILAR cycles, the power conversion efficiency was improved, according to the current density to voltage (J–V) analysis. The power conversion efficiency for 50 SILAR cycles is 1.33%, which is noticeable when compared to 30 and 40 SILAR cycles. [ABSTRACT FROM AUTHOR]

Published
2024
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