Abu Bakr Nassr - Academia.edu (original) (raw)

Papers by Abu Bakr Nassr

Research paper thumbnail of Cu@Pt/Cnt Catalysts for Oxygen Reduction Prepared by a Facile Two-Step Synthesis: Chemical vs. Electrochemical Leaching

Research paper thumbnail of Electrooxidation of Methanol on Carbon Supported Pt-Ru Nanocatalysts Prepared by Ethanol Reduction Method

International Journal of Electrochemical Science

Carbon Supported PtRu nanocatalysts have been prepared by simple impregnation reduction method in... more Carbon Supported PtRu nanocatalysts have been prepared by simple impregnation reduction method in which Pt and Ru precursors are reduced by ethanol under reflux conditions for different reaction times. The prepared nanocatalysts were characterized by means of XRD, EDAX, ICP-AAS, FESEM and TEM. XRD analyses showed that all nanocatalysts exhibited f.c.c crystal structure, the structure characteristic for pure Pt, except for that reduced at prolonged reaction time of 4h which showed the presence of characteristic peak for Ru metal. The lattice constant calculations indicate that all catalysts are present in unalloyed phase and the average particle size as determined by TEM was in the range of 3.7 nm. The electrocatalytic activities and stability for the prepared nanocatalysts methanol electrooxidation reaction (MOR) were studied by cyclic voltammetry. The catalysts prepared at 2h reduction time showed higher electrocatalytic activity in terms of mass specific activity and good stability over potential sweep for 100 cycles for methanol electro-oxidation. The results showed that the prepared nanocatalysts are considered as promising electrode catalyst (anode catalyst) for electro-oxidation of methanol in direct methanol fuel cells.

Research paper thumbnail of Development of nanostructured materials for PEM fuel cells application

Mit Flüssigbrennstoffen betriebene Brennstoffzellen (direct liquid fuel cells, DLFC) haben als au... more Mit Flüssigbrennstoffen betriebene Brennstoffzellen (direct liquid fuel cells, DLFC) haben als aussichtsreiche Energiequelle für elektronische Kleingeräte und tragbare Anwendungen viel Aufmerksamkeit erhalten. Diese Arbeit zielt auf die Entwicklung von hoch aktiven und beständigen Elektrokatalysatoren für die Anwendung in DLFCs. Es wurden nanostrukturierte Katalysatorsysteme geträgert auf mehrwandigen Kohlenstoffnanoröhren (MWCNTs), als Katalysatoren für die Methanol- sowie für die Ameisensäure-Oxidation dargestellt. Diese wurden mit strukturaufklärenden und elektrochemischen Methoden charakterisiert, um ihre strukturellen Eigenschaften zu untersuchen und ihre elektrokatalytische Aktivität gegenüber ausgewählten Elektrooxidationsreaktionen zu bewerten. Die elektrochemische Charakterisierung verdeutlichte, dass die Katalysatoren höher Aktivität für die Methanol und Ameisensäure-Elektroxidationund höhere Stabilität als industrielle Katalysatoren zeigte. In Versuchen mit der Direkt-Met...

Research paper thumbnail of Free-Standing Working Electrodes for Supercapacitors Based on Composite Polymer Nanofibers and Functionalized with Graphene Oxide

Journal of Electronic Materials, 2021

Hybrid capacitors have the potential to combine the benefits of both electrochemical double-layer... more Hybrid capacitors have the potential to combine the benefits of both electrochemical double-layer capacitors and faradaic capacitors. Supercapacitor electrodes can combine carbon-based and conductive polymers to achieve this potential and to deliver energy more than dielectric capacitors, and power densities more than Li-ion batteries. Polyindole (PIND) is a promising candidate for supercapacitors due to its unique physical and electrochemical properties. PIND was prepared chemically via oxidative polymerization. A laboratory-made electrospinning method has been successfully utilized to manufacture nanofibers from a blend of PIND and ultrahigh molecular weight polyacrylonitrile (PAN) to impart adequate chain entanglements. A tiny amount of graphene oxide (GO) was introduced to a solution of PIND/PAN before electrospinning to yield PIND/PAN/GO nanofibers to further improve the stability and conductivity of the electrodes. The chemical structure of the synthesized materials was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR). The electrochemical behavior of the prepared nanofibers was tested via the measurements of galvanostatic charge–discharge (GCD) and cyclic voltammetry (CV). It was found that the PIND/PAN/GO nanofiber webs exhibited a specific capacitance of 4960 mF g−1 which is higher than that of PIND/PAN nanofiber webs (1810 mF g−1) in 1 M H2SO4, at the same scanning rate in CV measurements. The results indicated that electrospinning as a cost-effective technique can be used successfully to fabricate free-standing electrodes from PIND, as well as illustrate the role of GO in enhancing the charge storage of PIND electrodes. Supercapacitor electrodes from PIND/PAN/GO nanofibers

Research paper thumbnail of Novel sulfonated poly(glycidyl methacrylate) grafted Nafion membranes for fuel cell applications

Polymer Bulletin, 2017

Nafion membranes have been modified by PGMA using persulphate initiation system, subsequent by su... more Nafion membranes have been modified by PGMA using persulphate initiation system, subsequent by sulfonation of PGMA graft branches, to convert the epoxy groups into sulfonic groups, which provide the modified membranes with more acidic sites to maintain its ionic conductivity. The grafting process and the sulfonation process have been confirmed by FT-IR, TGA and FT-IR, EDAX analysis and ion exchange capacity measurements, frequently. Moreover, the physicochemical properties of the modified membranes, such as water and methanol uptakes, and ion exchange capacity, have been studied. The results showed that the modified membranes have high water uptake. The ion exchange capacity measurements proved the conversion of the epoxy groups into sulfonic groups in the sulfonated grafted membranes since the sulfonated grafted membranes showed ion exchange capacity higher than that of grafted membranes. Also, the results showed that the modification process has no impact effect on the stability of the membranes dimensions in water and methanol. TGA analysis showed that the modified membranes exhibited high thermal stability than that of unmodified Nafion membranes. SEM analysis showed the homogeneity of the PGMA in the matrix of Nafion membrane. The methanol permeability of the modified membranes decreased with

Research paper thumbnail of Platinum–Dysprosium Alloys as Oxygen Electrodes in Alkaline Media: An Experimental and Theoretical Study

Nanomaterials

Platinum–dysprosium (Pt–Dy) alloys prepared by the arc melting technique are assessed as potentia... more Platinum–dysprosium (Pt–Dy) alloys prepared by the arc melting technique are assessed as potential electrodes for the oxygen reduction reaction (ORR) using voltammetry and chronoamperometry in alkaline media. A relatively small change (10 at.%) in the alloy composition brought a notable difference in the alloys’ performance for the ORR. Pt40Dy60 electrode, i.e., the electrode with a lower amount of Pt, was identified to have a higher activity towards ORR as evidenced by lower overpotential and higher current densities under identical experimental conditions. Furthermore, DFT calculations point out the unique single-atom-like coordination and electronic structure of Pt atoms in the Pt40Dy60 surface as responsible for enhanced ORR activity compared to the alloy with a higher Pt content. Additionally, Pt–Dy alloys showed activity in the oxygen evolution reaction (OER), with the OER current density lower than that of pure Pt.

Research paper thumbnail of High Compositional Dependence of Activity of Platinum–Dysprosium Alloys for Oxygen Reduction in Alkaline Media: Experimental and Theoretical Study

SSRN Electronic Journal, 2021

Research paper thumbnail of Honeycomb carbon obtained from coal liquefaction residual asphaltene for high-performance supercapacitors in ionic and organic liquid-based electrolytes

Journal of Energy Storage

Research paper thumbnail of Modifying the 316L stainless steel surface by an electrodeposition technique: towards high-performance electrodes for alkaline water electrolysis

Sustainable Energy & Fuels, 2022

A simple electrodeposition process has been used to modify the stainless steel surface with nicke... more A simple electrodeposition process has been used to modify the stainless steel surface with nickel phosphide nanoparticles for use as a highly active, stable, and inexpensive OER/HER bifunctional electrocatalyst in alkaline overall water splitting.

Research paper thumbnail of Stainless steel as gas evolving electrodes in water electrolysis: Enhancing the activity for hydrogen evolution reaction via electrodeposition of Co and CoP catalysts

International Journal of Hydrogen Energy

Research paper thumbnail of Hybrid electrocatalyst of CoFe2O4 decorating carbon spheres for alkaline oxygen evolution reaction

Research paper thumbnail of Contrasting the EXAFS obtained under air and H2 environments to reveal details of the surface structure of Pt–Sn nanoparticles

Physical Chemistry Chemical Physics

Details of the surface structure of bimetallic catalysts, essential in heterogeneous and electro-... more Details of the surface structure of bimetallic catalysts, essential in heterogeneous and electro-catalysis, obtained by analysis of EXAFS data under different atmospheres.

Research paper thumbnail of A simple microwave process for the preparation of cobalt oxide nanoparticles supported on carbon nanotubes for electrocatalytic applications

Journal of Solid State Electrochemistry

Research paper thumbnail of Facile and simple deposition of cobalt oxide onto oxidized multiwall carbon nanotubes for electrocatalytic oxygen reduction

Journal of Materials Science: Materials in Electronics

Research paper thumbnail of {"__content__"=>"Effects of heat treatment atmosphere on the structure and activity of PtSn nanoparticle electrocatalysts: a characterisation case study.", "sub"=>{"__content__"=>"3"}}

Faraday discussions, Jan 3, 2018

Comprehensive identification of the phases and atomic configurations of bimetallic nanoparticle c... more Comprehensive identification of the phases and atomic configurations of bimetallic nanoparticle catalysts are critical in understanding structure-property relationships in catalysis. However, control of the structure, whilst retaining the same composition, is challenging. Here, the same carbon supported Pt3Sn catalyst is annealed under air, Ar and H2 resulting in variation of the extent of alloying of the two components. The atmosphere-induced extent of alloying is characterised using a variety of methods including TEM, XRD, XPS, XANES and EXAFS and is defined as the fraction of Sn present as Sn0 (XPS and XANES) or the ratio of the calculated composition of the bimetallic particle to the nominal composition according to the stoichiometric ratio of the preparation (TEM, XRD and EXAFS). The values obtained depend on the structural method used, but the trend air < Ar < H2 annealed samples is consistent. These results are then used to provide insights regarding the electrocatalyti...

Research paper thumbnail of Electrodeposited cobalt oxide nanoparticles modified carbon nanotubes as a non-precious catalyst electrode for oxygen reduction reaction

Journal of Applied Electrochemistry, 2016

Research paper thumbnail of Nanostructured PtRu alloys as electrocatalyst for direct methanol fuel cells applications

AEJ - Alexandria Engineering Journal

Research paper thumbnail of Supporting information

Research paper thumbnail of Pd FAO 2

Research paper thumbnail of Supporting Informations

Research paper thumbnail of Cu@Pt/Cnt Catalysts for Oxygen Reduction Prepared by a Facile Two-Step Synthesis: Chemical vs. Electrochemical Leaching

Research paper thumbnail of Electrooxidation of Methanol on Carbon Supported Pt-Ru Nanocatalysts Prepared by Ethanol Reduction Method

International Journal of Electrochemical Science

Carbon Supported PtRu nanocatalysts have been prepared by simple impregnation reduction method in... more Carbon Supported PtRu nanocatalysts have been prepared by simple impregnation reduction method in which Pt and Ru precursors are reduced by ethanol under reflux conditions for different reaction times. The prepared nanocatalysts were characterized by means of XRD, EDAX, ICP-AAS, FESEM and TEM. XRD analyses showed that all nanocatalysts exhibited f.c.c crystal structure, the structure characteristic for pure Pt, except for that reduced at prolonged reaction time of 4h which showed the presence of characteristic peak for Ru metal. The lattice constant calculations indicate that all catalysts are present in unalloyed phase and the average particle size as determined by TEM was in the range of 3.7 nm. The electrocatalytic activities and stability for the prepared nanocatalysts methanol electrooxidation reaction (MOR) were studied by cyclic voltammetry. The catalysts prepared at 2h reduction time showed higher electrocatalytic activity in terms of mass specific activity and good stability over potential sweep for 100 cycles for methanol electro-oxidation. The results showed that the prepared nanocatalysts are considered as promising electrode catalyst (anode catalyst) for electro-oxidation of methanol in direct methanol fuel cells.

Research paper thumbnail of Development of nanostructured materials for PEM fuel cells application

Mit Flüssigbrennstoffen betriebene Brennstoffzellen (direct liquid fuel cells, DLFC) haben als au... more Mit Flüssigbrennstoffen betriebene Brennstoffzellen (direct liquid fuel cells, DLFC) haben als aussichtsreiche Energiequelle für elektronische Kleingeräte und tragbare Anwendungen viel Aufmerksamkeit erhalten. Diese Arbeit zielt auf die Entwicklung von hoch aktiven und beständigen Elektrokatalysatoren für die Anwendung in DLFCs. Es wurden nanostrukturierte Katalysatorsysteme geträgert auf mehrwandigen Kohlenstoffnanoröhren (MWCNTs), als Katalysatoren für die Methanol- sowie für die Ameisensäure-Oxidation dargestellt. Diese wurden mit strukturaufklärenden und elektrochemischen Methoden charakterisiert, um ihre strukturellen Eigenschaften zu untersuchen und ihre elektrokatalytische Aktivität gegenüber ausgewählten Elektrooxidationsreaktionen zu bewerten. Die elektrochemische Charakterisierung verdeutlichte, dass die Katalysatoren höher Aktivität für die Methanol und Ameisensäure-Elektroxidationund höhere Stabilität als industrielle Katalysatoren zeigte. In Versuchen mit der Direkt-Met...

Research paper thumbnail of Free-Standing Working Electrodes for Supercapacitors Based on Composite Polymer Nanofibers and Functionalized with Graphene Oxide

Journal of Electronic Materials, 2021

Hybrid capacitors have the potential to combine the benefits of both electrochemical double-layer... more Hybrid capacitors have the potential to combine the benefits of both electrochemical double-layer capacitors and faradaic capacitors. Supercapacitor electrodes can combine carbon-based and conductive polymers to achieve this potential and to deliver energy more than dielectric capacitors, and power densities more than Li-ion batteries. Polyindole (PIND) is a promising candidate for supercapacitors due to its unique physical and electrochemical properties. PIND was prepared chemically via oxidative polymerization. A laboratory-made electrospinning method has been successfully utilized to manufacture nanofibers from a blend of PIND and ultrahigh molecular weight polyacrylonitrile (PAN) to impart adequate chain entanglements. A tiny amount of graphene oxide (GO) was introduced to a solution of PIND/PAN before electrospinning to yield PIND/PAN/GO nanofibers to further improve the stability and conductivity of the electrodes. The chemical structure of the synthesized materials was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR). The electrochemical behavior of the prepared nanofibers was tested via the measurements of galvanostatic charge–discharge (GCD) and cyclic voltammetry (CV). It was found that the PIND/PAN/GO nanofiber webs exhibited a specific capacitance of 4960 mF g−1 which is higher than that of PIND/PAN nanofiber webs (1810 mF g−1) in 1 M H2SO4, at the same scanning rate in CV measurements. The results indicated that electrospinning as a cost-effective technique can be used successfully to fabricate free-standing electrodes from PIND, as well as illustrate the role of GO in enhancing the charge storage of PIND electrodes. Supercapacitor electrodes from PIND/PAN/GO nanofibers

Research paper thumbnail of Novel sulfonated poly(glycidyl methacrylate) grafted Nafion membranes for fuel cell applications

Polymer Bulletin, 2017

Nafion membranes have been modified by PGMA using persulphate initiation system, subsequent by su... more Nafion membranes have been modified by PGMA using persulphate initiation system, subsequent by sulfonation of PGMA graft branches, to convert the epoxy groups into sulfonic groups, which provide the modified membranes with more acidic sites to maintain its ionic conductivity. The grafting process and the sulfonation process have been confirmed by FT-IR, TGA and FT-IR, EDAX analysis and ion exchange capacity measurements, frequently. Moreover, the physicochemical properties of the modified membranes, such as water and methanol uptakes, and ion exchange capacity, have been studied. The results showed that the modified membranes have high water uptake. The ion exchange capacity measurements proved the conversion of the epoxy groups into sulfonic groups in the sulfonated grafted membranes since the sulfonated grafted membranes showed ion exchange capacity higher than that of grafted membranes. Also, the results showed that the modification process has no impact effect on the stability of the membranes dimensions in water and methanol. TGA analysis showed that the modified membranes exhibited high thermal stability than that of unmodified Nafion membranes. SEM analysis showed the homogeneity of the PGMA in the matrix of Nafion membrane. The methanol permeability of the modified membranes decreased with

Research paper thumbnail of Platinum–Dysprosium Alloys as Oxygen Electrodes in Alkaline Media: An Experimental and Theoretical Study

Nanomaterials

Platinum–dysprosium (Pt–Dy) alloys prepared by the arc melting technique are assessed as potentia... more Platinum–dysprosium (Pt–Dy) alloys prepared by the arc melting technique are assessed as potential electrodes for the oxygen reduction reaction (ORR) using voltammetry and chronoamperometry in alkaline media. A relatively small change (10 at.%) in the alloy composition brought a notable difference in the alloys’ performance for the ORR. Pt40Dy60 electrode, i.e., the electrode with a lower amount of Pt, was identified to have a higher activity towards ORR as evidenced by lower overpotential and higher current densities under identical experimental conditions. Furthermore, DFT calculations point out the unique single-atom-like coordination and electronic structure of Pt atoms in the Pt40Dy60 surface as responsible for enhanced ORR activity compared to the alloy with a higher Pt content. Additionally, Pt–Dy alloys showed activity in the oxygen evolution reaction (OER), with the OER current density lower than that of pure Pt.

Research paper thumbnail of High Compositional Dependence of Activity of Platinum–Dysprosium Alloys for Oxygen Reduction in Alkaline Media: Experimental and Theoretical Study

SSRN Electronic Journal, 2021

Research paper thumbnail of Honeycomb carbon obtained from coal liquefaction residual asphaltene for high-performance supercapacitors in ionic and organic liquid-based electrolytes

Journal of Energy Storage

Research paper thumbnail of Modifying the 316L stainless steel surface by an electrodeposition technique: towards high-performance electrodes for alkaline water electrolysis

Sustainable Energy & Fuels, 2022

A simple electrodeposition process has been used to modify the stainless steel surface with nicke... more A simple electrodeposition process has been used to modify the stainless steel surface with nickel phosphide nanoparticles for use as a highly active, stable, and inexpensive OER/HER bifunctional electrocatalyst in alkaline overall water splitting.

Research paper thumbnail of Stainless steel as gas evolving electrodes in water electrolysis: Enhancing the activity for hydrogen evolution reaction via electrodeposition of Co and CoP catalysts

International Journal of Hydrogen Energy

Research paper thumbnail of Hybrid electrocatalyst of CoFe2O4 decorating carbon spheres for alkaline oxygen evolution reaction

Research paper thumbnail of Contrasting the EXAFS obtained under air and H2 environments to reveal details of the surface structure of Pt–Sn nanoparticles

Physical Chemistry Chemical Physics

Details of the surface structure of bimetallic catalysts, essential in heterogeneous and electro-... more Details of the surface structure of bimetallic catalysts, essential in heterogeneous and electro-catalysis, obtained by analysis of EXAFS data under different atmospheres.

Research paper thumbnail of A simple microwave process for the preparation of cobalt oxide nanoparticles supported on carbon nanotubes for electrocatalytic applications

Journal of Solid State Electrochemistry

Research paper thumbnail of Facile and simple deposition of cobalt oxide onto oxidized multiwall carbon nanotubes for electrocatalytic oxygen reduction

Journal of Materials Science: Materials in Electronics

Research paper thumbnail of {"__content__"=>"Effects of heat treatment atmosphere on the structure and activity of PtSn nanoparticle electrocatalysts: a characterisation case study.", "sub"=>{"__content__"=>"3"}}

Faraday discussions, Jan 3, 2018

Comprehensive identification of the phases and atomic configurations of bimetallic nanoparticle c... more Comprehensive identification of the phases and atomic configurations of bimetallic nanoparticle catalysts are critical in understanding structure-property relationships in catalysis. However, control of the structure, whilst retaining the same composition, is challenging. Here, the same carbon supported Pt3Sn catalyst is annealed under air, Ar and H2 resulting in variation of the extent of alloying of the two components. The atmosphere-induced extent of alloying is characterised using a variety of methods including TEM, XRD, XPS, XANES and EXAFS and is defined as the fraction of Sn present as Sn0 (XPS and XANES) or the ratio of the calculated composition of the bimetallic particle to the nominal composition according to the stoichiometric ratio of the preparation (TEM, XRD and EXAFS). The values obtained depend on the structural method used, but the trend air < Ar < H2 annealed samples is consistent. These results are then used to provide insights regarding the electrocatalyti...

Research paper thumbnail of Electrodeposited cobalt oxide nanoparticles modified carbon nanotubes as a non-precious catalyst electrode for oxygen reduction reaction

Journal of Applied Electrochemistry, 2016

Research paper thumbnail of Nanostructured PtRu alloys as electrocatalyst for direct methanol fuel cells applications

AEJ - Alexandria Engineering Journal

Research paper thumbnail of Supporting information

Research paper thumbnail of Pd FAO 2

Research paper thumbnail of Supporting Informations