Publications by authors named "Muhammad Wakeel"

7 Publications

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Impact of Bi Doping into Boron Nitride Nanosheets on Electronic and Optical Properties Using Theoretical Calculations and Experiments.

Nanoscale Res Lett 2021 May 12;16(1):82. Epub 2021 May 12.

Department of Physics, College of Science, King Faisal University, P.O. Box 400, Al-Ahsa, 31982, Saudi Arabia.

In the present work, boron nitride (BN) nanosheets were prepared through bulk BN liquid phase exfoliation while various wt. ratios (2.5, 5, 7.5 and 10) of bismuth (Bi) were incorporated as dopant using hydrothermal technique. Our findings exhibit that the optical investigation showed absorption spectra in near UV region. Density functional theory calculations indicate that Bi doping has led to various modifications in the electronic structures of BN nanosheet by inducing new localized gap states around the Fermi level. It was found that bandgap energy decrease with the increase of Bi dopant concentrations. Therefore, in analysis of the calculated absorption spectra, a redshift has been observed in the absorption edges, which is consistent with the experimental observation. Additionally, host and Bi-doped BN nanosheets were assessed for their catalytic and antibacterial potential. Catalytic activity of doped free and doped BN nanosheets was evaluated by assessing their performance in dye reduction/degradation process. Bactericidal activity of Bi-doped BN nanosheets resulted in enhanced efficiency measured at 0-33.8% and 43.4-60% against S. aureus and 0-38.8% and 50.5-85.8% against E. coli, respectively. Furthermore, In silico molecular docking predictions were in good agreement with in-vitro bactericidal activity. Bi-doped BN nanosheets showed good binding score against DHFR of E. coli (- 11.971 kcal/mol) and S. aureus (- 8.526 kcal/mol) while binding score for DNA gyrase from E. coli (- 6.782 kcal/mol) and S. aureus (- 7.819 kcal/mol) suggested these selected enzymes as possible target.
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http://dx.doi.org/10.1186/s11671-021-03542-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116421PMC
May 2021

Unveiling land footprint of solar power: A pilot solar tower project in China.

J Environ Manage 2021 Feb 23;280:111741. Epub 2020 Dec 23.

Department of Environmental Sciences, COMSATS University Islamabad (CUI), Vehari Campus, Pakistan.

Land occupation by solar power installations has become a rising concern that may cause adverse impacts on natural ecosystems and biodiversity. Existing studies mainly adopt a local perspective to view land use requirements of solar power and forget that the solar-based electricity system is subordinate to the macro economy and nourished by the material, machinery and service support by various economic sectors. To manifest a key aspect of the footprint of solar power on land resources, this study uncovered the extensive industrial land use initiated by the infrastructure of a representative pilot solar-based electricity plant using a systems perspective. The results in this study show that in magnitude, land footprint by the infrastructure of the pilot solar plant amounts to three times as much as the onsite land area. Also, the land footprint calculated is revealed as one order of magnitude larger than a previous finding that includes primary materials only, and four to seven times higher than the onsite land use by coal-based electricity plants. The outcome implies that existing environmental management policies need to be re-evaluated by putting enough emphasis on the land displacement by solar power systems along the production chain.
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http://dx.doi.org/10.1016/j.jenvman.2020.111741DOI Listing
February 2021

High Performance Tandem Solar Cells with Inorganic Perovskite and Organic Conjugated Molecules to Realize Complementary Absorption.

J Phys Chem Lett 2020 Nov 29;11(22):9596-9604. Epub 2020 Oct 29.

Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.

All-inorganic halide perovskite solar cells (PerSCs) have achieved rapid development in recent years. However, limited by narrow absorption bands, the power conversion efficiency (PCE) of all-inorganic halide PerSCs lag behind the organic-inorganic hybrid ones. In this contribution, to expand their absorption spectra and enhance the PCE, tandem solar cells (TSCs) with inorganic perovskite and organic conjugated molecules are constructed, utilizing CsPbIBr as an ultraviolet-visible light absorber and a PTB7-Th:IEICO-4F bulk-heterojunction (BHJ) active layer as a near-infrared light absorber. To physically and electronically connect the front and rear subcells, P3HT/MoO/Ag/PFN-Br is introduced as an interconnecting junction. Finally, the TSCs exhibit a remarkably higher PCE of 17.24% compared to that of the single junction PerSCs (12.09%) and organic solar cells (OSCs) (10.89%). These results indicate that the combination of all-inorganic perovskite and a low bandgap organic active layer for TSCs is a feasible approach to realize broad spectra utilization and efficiency enhancement.
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http://dx.doi.org/10.1021/acs.jpclett.0c02794DOI Listing
November 2020

A simple method for preparing ultra-light graphene aerogel for rapid removal of U(VI) from aqueous solution.

Environ Pollut 2019 Aug 9;251:547-554. Epub 2019 May 9.

Key Laboratory of Photovoltaic and Energy Conservation Materials, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, 230031, Anhui, PR China; NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia. Electronic address:

In this study, graphene aerogel (GA) was successfully prepared through a simple hydrothermal method. The resulting GA exhibited a porous network structure with a large specific surface area (350.8 m/g), ultra-light mass and easy separation from water. The pH value of the GA was estimated to be 3.5. The adsorption process and the factors that affect adsorption capacity were studied. The adsorption could be conducted in a wide pH range from 2.0 to 7.0. The maximum adsorption capacity of GA towards U(VI) at pH 4.0 and T = 298 K was 238.67 mg/g calculated from the Langmuir model. The GA had greatly rapid adsorption property for the removal of U(VI) at pH 4.0. Kinetic data showed good correlation with pseudo-second-order equation. Fourier transform infrared spectroscopy and X-ray photoelectron spectrometry characterizations showed that GA adsorbed U(VI) through chemical interaction by oxygen-containing and nitrogen-containing groups functional groups. The results show that GA has excellent application potential as an adsorbent material for removing U(VI) from aqueous solution.
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http://dx.doi.org/10.1016/j.envpol.2019.05.011DOI Listing
August 2019

Gamma-ferric oxide nanoparticles decoration onto porous layered double oxide belts for efficient removal of uranyl.

J Colloid Interface Sci 2019 Feb 4;535:265-275. Epub 2018 Oct 4.

CAS Key Laboratory of Photovoltaic and Energy Conservation Materials, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, PR China. Electronic address:

Layered double oxides (LDO) and γ-FeO have been demonstrated to be promising adsorbents to remove radioactive elements from aqueous media. Herein, magnetic γ-FeO nanoparticles decoration onto porous layered double oxides belts (γ-FeO/LDO) were fabricated by in situ solid-state thermolysis technique combined with Fe(III)-loaded layered double hydroxides as a precursor. The microstructure, chemical composition, and magnetic properties of γ-FeO/LDO were characterized in detail. The as-obtained γ-FeO/LDO was employed as an adsorbent for the elimination of U(VI) from water. The adsorption process followed the Langmuir model with the maximal adsorption capacity of U(VI) onto γ-FeO/LDO being 526.32 mg·g at 303 K and pH 5, which surpassed pristine LDO and many other materials. The Fourier transformed infrared spectra and the X-ray photoelectron spectra analysis suggested that the interaction mechanism was mainly controlled by the surface complexation and electrostatic interactions. All in all, the γ-FeO/LDO with remarkable adsorption capacity, excellent regeneration, and easy magnetic separation opens a new expectation as a suitable material for the cleanup of U(VI) from contaminated water.
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http://dx.doi.org/10.1016/j.jcis.2018.10.005DOI Listing
February 2019

Layered Heterostructures of Ultrathin Polymeric Carbon Nitride and ZnIn S Nanosheets for Photocatalytic CO Reduction.

Chemistry 2018 Dec 1;24(69):18529-18534. Epub 2018 Oct 1.

State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350002, P. R. China.

The rational construction of heterostructures by using layered semiconductors with two-dimensional (2D) nanosheet configurations is promising to improve the efficiency of CO photoreduction. Herein, the fabrication of layered heterojunction photocatalysts (PCN/ZnIn S ) by in situ growth of 2D ZnIn S nanosheets on the surfaces of ultrathin polymeric carbon nitride (PCN) layers is presented for greatly enhanced CO conversion with visible light. The solution-processed self-assembly strategy renders the building of uniform and intimate junctions between PCN layers and ZnIn S subunits, which remarkably accelerates the separation and transfer of photogenerated charge carriers. In addition, the layered composites can also promote CO adsorption and strengthen the visible-light absorption. Consequently, the optimized PCN/ZnIn S sheet-shaped composite shows reinforced photoactivity for deoxygenative CO conversion, affording a high CO-production rate of 44.6 μmol h , which is 223 times higher than that of the pristine PCN nanosheets. Moreover, the heterojunction photocatalyst also exhibits high stability during repeated runs for five cycles.
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http://dx.doi.org/10.1002/chem.201803250DOI Listing
December 2018

Modulating Crystallinity of Graphitic Carbon Nitride for Photocatalytic Oxidation of Alcohols.

ChemSusChem 2017 11 4;10(22):4451-4456. Epub 2017 Oct 4.

State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350002, P.R. China.

Exploiting efficient photocatalysts with strengthened structure for solar-driven alcohol oxidation is of great significance. The photocatalytic performance of graphitic carbon nitrides can be considerably promoted by modulating its crystallinity. Results confirmed that a high crystallinity accelerates the separation and transfer of photogenerated charge carriers, thus providing more free charges for photoredox reactions. More importantly, the high crystallinity facilitated the adsorption of benzyl alcohol and desorption of benzaldehyde and simultaneously lowered the energy barrier for O activation. As a result, the crystalline carbon nitride exhibited a roughly twelvefold promotion with respect to the normal carbon nitride. The remarkable enhancement of activity can be attributed to the synergistic effects of increased electron-hole separation and increased surface reaction kinetics. These findings will open up new opportunities to modulate the structure of polymers for a wide variety of organic reactions.
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http://dx.doi.org/10.1002/cssc.201701392DOI Listing
November 2017