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Your search keyword '"Mehmood, Shahid"' showing total 48 results
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48 results on '"Mehmood, Shahid"'

4. Effect of salinity stress and surfactant treatment with zinc and boron on morpho-physiological and biochemical indices of fenugreek (Trigonella foenum-graecum)

Author

Khan, Atika, primary, Bibi, Safura, additional, Javed, Talha, additional, Mahmood, Athar, additional, Mehmood, Shahid, additional, Javaid, Muhammad Mansoor, additional, Ali, Baber, additional, Yasin, Muhammad, additional, Abidin, Zain Ul, additional, Al-Sadoon, Mohammad Khalid, additional, Babar, Babar Hussain, additional, Iqbal, Rashid, additional, and Malik, Tabarak, additional

Published
2024
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12. Microwave assisted synthesis of Mn3O4 nanograins intercalated into reduced graphene oxide layers as cathode material for alternative clean power generation energy device

Author

Mehmood Shahid, Thilina Rajeendre Katugampalage, Mohammad Khalid, Waqar Ahmed, Chariya Kaewsaneha, Paiboon Sreearunothai, and Pakorn Opaprakasit

Subjects
Multidisciplinary
Abstract

Mn3O4 nanograins incorporated into reduced graphene oxide as a nanocomposite electrocatalyst have been synthesized via one-step, facile, and single-pot microwave-assisted hydrothermal technique. The nanocomposites were employed as cathode material of fuel cells for oxygen reduction reaction (ORR). The synthesized product was thoroughly studied by using important characterization, such as XRD for the structure analysis and FESEM and TEM analyses to assess the morphological structures of the material. Raman spectra were employed to study the GO, rGO bands and formation of Mn3O4@rGO nanocomposite. FTIR and UV–Vis spectroscopic analysis were used to verify the effective synthesis of the desired electrocatalyst. The Mn3O4@rGO-10% nanocomposite with 10 wt% of graphene oxide was used to alter the shiny surface of the working electrode and applied for ORR in O2 purged 0.5 M KOH electrolyte solution. The Mn3O4@rGO-10% nanocomposite electrocatalyst exhibited outstanding performance with an improved current of − 0.738 mA/cm2 and shifted overpotential values of − 0.345 V when compared to other controlled electrodes, including the conventionally used Pt/C catalyst generally used for ORR activity. The tolerance of Mn3O4@rGO-10% nanocomposite was tested by injecting a higher concentration of methanol, i.e., 0.5 M, and found unsusceptible by methanol crossover. The stability test of the synthesized electrocatalyst after 3000 s was also considered, and it demonstrated excellent current retention of 98% compared to commercially available Pt/C electrocatalyst. The synthesized nanocomposite material could be regarded as an effective and Pt-free electrocatalyst for practical ORR that meets the requirement of low cost, facile fabrication, and adequate stability.

Published
2022

15. Photoelectrochemical reduction of dissolved carbon dioxide over Ni(OH)2 into organic oxygenates

Author

Muhammad Mehmood Shahid, Wan Jefrey Basirun, and Ahmad Nazeer Che Mat

Subjects
Materials science, Aqueous solution, 010405 organic chemistry, Formic acid, Non-blocking I/O, General Chemistry, 010402 general chemistry, Electrochemistry, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Photoelectrolysis, Methanol, Fourier transform infrared spectroscopy, Nuclear chemistry, BET theory
Abstract

The hydrothermal method has been used to prepare Ni(OH)2 photocathode. The photoelectrochemical (PEC) reduction of CO2 over Ni(OH)2 has been conducted in 0.2 M LiClO4 in aqueous and N,N-dimethylformamide (DMF) medium under visible light irradiation. The thin film was characterized by XRD, UV–Vis, FTIR, FESEM-EDX, BET analysis, and electrochemical method for the determination of phases, bandgap energy, chemical bonding, surface morphology, elemental compositions, surface area, and electrochemical properties, respectively. Based on UV–Vis spectroscopy, the bandgap energy of Ni(OH)2 was 1.8 eV which enabled efficient visible light absorption for the photoreaction. The photocurrent density in aqueous and DMF solution at 0.2 V (vs. Ag/AgCl) was 24 mA cm−2 and 5 mA cm−2, respectively. Acetaldehyde and methanol are the products in aqueous solution, while formic acid and methanol are the products in DMF, after 6 h of photoelectrolysis. The product formations from the photoelectrochemical reduction of dissolved CO2 were 612 and 854 ppm in aqueous and DMF, respectively, where the Faradaic efficiency in aqueous and DMF is 24 and 33%, respectively. Furthermore, throughout the PEC study, the transformation of Ni(OH)2 to NiO plays a significant role in the formation of organic oxygenates from the reduction reaction of CO2.

Published
2021

19. Amperometric detection of hydrogen peroxide and its density functional theory for adsorption on Ag/TiO2 nanohybrid

Author

Nay Ming Huang, Liming Che, Muhammad Mehmood Shahid, Su Pei Lim, and Perumal Rameshkumar

Subjects
010302 applied physics, Detection limit, Materials science, Nanocomposite, Condensed Matter Physics, Electrochemistry, 01 natural sciences, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Electron transfer, chemistry.chemical_compound, Adsorption, Chemical engineering, chemistry, 0103 physical sciences, Electrode, Density functional theory, Electrical and Electronic Engineering, Hydrogen peroxide
Abstract

Silver/titania (Ag/TiO2) nanocomposites, synthesized through a simple one-step chemical reduction method, are used for electrochemical sensing of hydrogen peroxide (H2O2). The images of transmission electron microscopic (TEM) demonstrate a well dispersion of Ag nanoparticles (NPs) with a particle size range of approximately 3 nm on the TiO2 surface, which makes the sensor based on Ag/TiO2 exhibit an excellent performance toward H2O2. The AgNPs presented in the nanocomposite exhibit electrocatalytic reduction of H2O2 and the limit of detection (LOD) is found to be 1.23 µM. Density functional theory (DFT) calculation studies reveal that H2O2 could be easily adsorbed onto Ag rather than TiO2 surface of Ag/TiO2 via a partial electron transfer from Ag to H2O2. The nanocomposite-modified electrode has also excellent selectivity toward the detection of H2O2 over the interferents even when the interferents have a 100 times higher concentration than H2O2.

Published
2020

21. Bioaccumulation and transfer of zinc in soil plant and animal system: a health risk assessment for the grazing animals

Author

Chen, Fu, primary, Muhammad, Fatima Ghulam, additional, Khan, Zafar Iqbal, additional, Ahmad, Kafeel, additional, Malik, Ifra Saleem, additional, Ashfaq, Asma, additional, Naeem, Majida, additional, Nadeem, Muhammad, additional, Ma, Jing, additional, Awan, Muhammad Umer Farooq, additional, Mahpara, Shahzadi, additional, and Mehmood, Shahid, additional

Published
2021
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23. Defect states in ZnO/SnO2 composite nanostructures (CNs) for possible facilitating role in carrier transport across the junction

Author

Sabeen, Madiha, primary, Aziz, Liaquat, additional, Nazir, Tahir, additional, Mehmood, Shahid, additional, Bhopal, Muhammad Fahad, additional, Ali, Awais, additional, Saeed, Faisal, additional, Nasim, Faisal, additional, Cepek, C., additional, Bhardwaj, S., additional, Ul-Hamid, Anwar, additional, and Bhatti, Arshad Saleem, additional

Published
2021
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26. Robust late twenty-first century shift in the regional monsoons in RegCM-CORDEX simulations

Author

Ashfaq, Moetasim, primary, Cavazos, Tereza, additional, Reboita, Michelle Simões, additional, Torres-Alavez, José Abraham, additional, Im, Eun-Soon, additional, Olusegun, Christiana Funmilola, additional, Alves, Lincoln, additional, Key, Kesondra, additional, Adeniyi, Mojisola O., additional, Tall, Moustapha, additional, Sylla, Mouhamadou Bamba, additional, Mehmood, Shahid, additional, Zafar, Qudsia, additional, Das, Sushant, additional, Diallo, Ismaila, additional, Coppola, Erika, additional, and Giorgi, Filippo, additional

Published
2020
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30. Amperometric detection of nitric oxide using a glassy carbon electrode modified with gold nanoparticles incorporated into a nanohybrid composed of reduced graphene oxide and Nafion

Author

Perumal Rameshkumar, Sheng-Tung Huang, Muhammad Mehmood Shahid, Nay Ming Huang, and Norazriena Yusoff

Subjects
Materials science, Graphene, Inorganic chemistry, Oxide, Nanochemistry, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Ascorbic acid, 01 natural sciences, Amperometry, 0104 chemical sciences, Analytical Chemistry, law.invention, chemistry.chemical_compound, chemistry, Colloidal gold, law, Nafion, Electrode, 0210 nano-technology
Abstract

The authors show that the electrocatalytic performance toward the detection of nitric oxide (NO) can be enhanced by making use of gold nanoparticles (AuNP) in a matrix consisting of reduced graphene oxide and Nafion (rGO-Nf). The rGO-Nf@Au nanohybrid was synthesized via a hydrothermal method. The spherical AuNP have diameters in the range from 50 to 200 nm as proven by field emission scanning electron microscopy (FESEM). A glassy carbon electrode (GCE) modified with the nanohybrid displays excellent electrocatalytic activity towards NO oxidation compared to other kinds of modified electrodes. Best operated at a voltage of +0.8 V (vs. SCE), the amperometric response was linear in the 1 μM to 0.16 mM nitrite concentration range, with 0.5 μM detection limit (at an S/N ratio of 3). The high surface area of the AuNP along with the synergistic effect of AuNP and rGO-Nf film on the signal current is believed to cause the enhanced electrocatalytic activity of the nanohybrid. The sensor is not interfered by dopamine (DA), ascorbic acid (AA), uric acid (UA), glucose, urea, and NaCl even in 5-fold higher concentrations. In our perception, the rGO-Nf@Au modified electrode is a promising tool for highly sensitive and selective amperometric sensing of NO.

Published
2017

31. Binary nanocomposite based on Co3O4 nanocubes and multiwalled carbon nanotubes as an ultrasensitive platform for amperometric determination of dopamine

Author

Muhammad Mehmood Shahid, K. P. Ramesh, Fatin Saiha Omar, Saqib Rafique, Singh Ramesh, Shahid Bashir, and Arshid Numan

Subjects
Nanocomposite, Materials science, Analytical chemistry, 02 engineering and technology, Carbon nanotube, Chronoamperometry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrocatalyst, 01 natural sciences, 0104 chemical sciences, Analytical Chemistry, law.invention, symbols.namesake, Chemical engineering, X-ray photoelectron spectroscopy, law, symbols, Cyclic voltammetry, 0210 nano-technology, Raman spectroscopy, High-resolution transmission electron microscopy
Abstract

Composites containing cobalt oxide (Co3O4) nanocubes integrated with multiwall carbon nanotubes (MWCNT) were synthesized by a hydrothermal route. The fractions of MWCNTs in the composite were varied from 4, 8, 12, 16 and 20 wt.%, and the resulting materials are denoted as C1, C2, C3, C4 and C5, respectively. The formation of products with high structural crystallinity was confirmed by X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray diffraction. A morphological study by field emission scanning electron microscopy and high resolution transmission electron microscopy showed the successful integration of Co3O4 nanocubes to the MWCNTs with an average particle size of ∼32 nm. The surface of a glassy carbon electrode (GCE) was modified with the nanocomposites in order to evaluate the electrochemical performance of the nanocomposites. Cyclic voltammetry showed that the C4-modified GCE displays best performance in terms of oxidation potential and peak current in comparison to that of a bare GCE, Co3O4 nanocubes, or GCEs modified with C1, C2, C3 or C5. The detection limit (at an S/N ratio of 3) is 0.176 nM by using chronoamperometry, and the linear range is between 1 and 20 μM.

Published
2017

36. A glassy carbon electrode modified with graphene oxide and silver nanoparticles for amperometric determination of hydrogen peroxide

Author

An'amt Mohamed Noor, Perumal Rameshkumar, Muhammad Mehmood Shahid, and Nay Ming Huang

Subjects
Working electrode, Graphene, Inorganic chemistry, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Ascorbic acid, Electrocatalyst, 01 natural sciences, Amperometry, Silver nanoparticle, 0104 chemical sciences, Analytical Chemistry, law.invention, chemistry.chemical_compound, chemistry, law, Cyclic voltammetry, 0210 nano-technology, Hydrogen peroxide
Abstract

The article describes a glassy carbon electrode (GCE) modified with a nanocomposite consisting of graphene oxide and silver nanoparticles, and its application to amperometric determination of hydrogen peroxide (H2O2). Cyclic voltammetry with this modified electrode reveals efficient electrocatalytic reduction of H2O2. The response to H2O2 at a working potential of −0.3 V (vs. Ag/AgCl) is linear in the 100 μM to 11 mM concentration range at pH 7.2. The limit of detection is 28.3 μM (at an S/N ratio of 3). Good selectivity is observed over physiological interferents such as dopamine, ascorbic acid, uric acid and glucose.

Published
2015

37. Significantly improved photovoltaic performance in polymer bulk heterojunction solar cells with graphene oxide /PEDOT:PSS double decked hole transport layer

Author

Khaulah Sulaiman, Saqib Rafique, Muhammad Mehmood Shahid, Shahino Mah Abdullah, and Mohammad Omaish Ansari

Subjects
Multidisciplinary, Materials science, Equivalent series resistance, Open-circuit voltage, Graphene, business.industry, Energy conversion efficiency, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Article, Polymer solar cell, 0104 chemical sciences, law.invention, PEDOT:PSS, law, Optoelectronics, Charge carrier, 0210 nano-technology, business, Short circuit
Abstract

This work demonstrates the high performance graphene oxide (GO)/PEDOT:PSS doubled decked hole transport layer (HTL) in the PCDTBT:PC71BM based bulk heterojunction organic photovoltaic device. The devices were tested on merits of their power conversion efficiency (PCE), reproducibility, stability and further compared with the devices with individual GO or PEDOT:PSS HTLs. Solar cells employing GO/PEDOT:PSS HTL yielded a PCE of 4.28% as compared to either of individual GO or PEDOT:PSS HTLs where they demonstrated PCEs of 2.77 and 3.57%, respectively. In case of single GO HTL, an inhomogeneous coating of ITO caused the poor performance whereas PEDOT:PSS is known to be hygroscopic and acidic which upon direct contact with ITO reduced the device performance. The improvement in the photovoltaic performance is mainly ascribed to the increased charge carriers mobility, short circuit current, open circuit voltage, fill factor, and decreased series resistance. The well matched work function of GO and PEDOT:PSS is likely to facilitate the charge transportation and an overall reduction in the series resistance. Moreover, GO could effectively block the electrons due to its large band-gap of ~3.6 eV, leading to an increased shunt resistance. In addition, we also observed the improvement in the reproducibility and stability.

Published
2017

38. Direct binding of CEP85 to STIL ensures robust PLK4 activation and efficient centriole assembly

Author

Liu, Yi, primary, Gupta, Gagan D., additional, Barnabas, Deepak D., additional, Agircan, Fikret G., additional, Mehmood, Shahid, additional, Wu, Di, additional, Coyaud, Etienne, additional, Johnson, Christopher M., additional, McLaughlin, Stephen H., additional, Andreeva, Antonina, additional, Freund, Stefan M. V., additional, Robinson, Carol V., additional, Cheung, Sally W. T., additional, Raught, Brian, additional, Pelletier, Laurence, additional, and van Breugel, Mark, additional

Published
2018
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43. Crystal structure of an invertebrate cytolysin pore reveals unique properties and mechanism of assembly

Author

Podobnik, Marjetka, primary, Savory, Peter, additional, Rojko, Nejc, additional, Kisovec, Matic, additional, Wood, Neil, additional, Hambley, Richard, additional, Pugh, Jonathan, additional, Wallace, E. Jayne, additional, McNeill, Luke, additional, Bruce, Mark, additional, Liko, Idlir, additional, Allison, Timothy M., additional, Mehmood, Shahid, additional, Yilmaz, Neval, additional, Kobayashi, Toshihide, additional, Gilbert, Robert J. C., additional, Robinson, Carol V., additional, Jayasinghe, Lakmal, additional, and Anderluh, Gregor, additional

Published
2016
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44. Super-complexes of adhesion GPCRs and neural guidance receptors

Author

Jackson, Verity A., primary, Mehmood, Shahid, additional, Chavent, Matthieu, additional, Roversi, Pietro, additional, Carrasquero, Maria, additional, del Toro, Daniel, additional, Seyit-Bremer, Goenuel, additional, Ranaivoson, Fanomezana M., additional, Comoletti, Davide, additional, Sansom, Mark S. P., additional, Robinson, Carol V., additional, Klein, Rüdiger, additional, and Seiradake, Elena, additional

Published
2016
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