19 results on '"MOSTAFA, A. O."'
Search Results
2. Coefficient bounds for a subclass of univalent functions of complex order associated with Chebyshev polynomials defined by q- derivative operator.
- Author
-
Aouf, M. K., Mostafa, A. O., and Al-Quhali, F. Y.
- Abstract
In this paper, we investigate a subclass L (q , b , α , t) by means of Chebyshev polynomials and q - derivative operator expansions of univalent functions of complex order in the open unit disk. Later, we find initial coefficients | a 2 | and | a 3 | and sharp bounds of Fekete–Szegő functional | a 3 - ξ a 2 2 | for functions in this subclass. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Coefficient Bounds for Multivalent Classes of Starlike and Convex Functions Defined by Higher-Order Derivatives and Complex Order.
- Author
-
Aouf, M. K., Mostafa, A. O., and Bulboacă, T.
- Subjects
- *
STAR-like functions , *CONVEX functions , *DIFFERENTIAL equations - Abstract
We establish coefficient bounds for functions from the subclasses of p-valent starlike and p-valent convex functions defined by higher-order derivatives and complex order introduced with the help of a certain nonhomogeneous Cauchy–Euler differential equation with higher-order derivatives. Relevant connections of some of our results with the results obtained earlier are provided. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Harmonic subclass of univalent functions defined by modified q-difference operator.
- Author
-
Mostafa, A. O. and Aouf, M. K.
- Abstract
In this paper, using q - difference operator, we define a class of harmonic univalent functions and obtain various properties for it. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. Certain subclasses of analytic functions with varying arguments associated with q-difference operator.
- Author
-
Aouf, M. K., Mostafa, A. O., and Elmorsy, R. E.
- Abstract
In this paper, we introduce the new classes V E q (n , λ , β) and V G q (n , λ , β) of analytic functions with varying arguments defined by q-Al-Oboudi difference operator and study different properties for them. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
6. Vitamin D receptor gene polymorphism in patients with osteomalacic myopathy in Egypt.
- Author
-
Shokri, Hossam M., Mohamed, Karim O., Fahmy, Nagia A., Mostafa, Ahmed O., and Ghareeb, Ahmed
- Subjects
VITAMIN D receptors ,GENETIC polymorphisms ,MUSCLE diseases ,SINGLE nucleotide polymorphisms ,VITAMIN D ,NEMALINE myopathy - Abstract
Introduction: Vitamin D works by binding to vitamin D receptor (VDR). The muscle involvement in hypovitaminosis D was broadly named osteomalacic myopathy. Methods: A case control study involved 20 female patients diagnosed with osteomalacic myopathy compared with 15 age-matched healthy female controls. We assessed both for VDR genotype single-nucleotide polymorphisms (SNP) at 3 sites (ApaI, BsmI, and FokI). Results: ApaI and BsmI genotypes distribution in both groups showed non-significant difference unlike FokI genotypes in which we found significantly higher percentages of single allele mutation in patients vs. controls. Conclusion: The relation of VDR gene SNPs to muscle function was studied before but in healthy subjects. We tried to correlate if presence/absence of a certain mutation is responsible for the appearance of osteomalacic myopathy. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
7. Fekete Szegö properties for a class of univalent functions of complex order associated with q-difference operator.
- Author
-
Aouf, M. K., Mostafa, A. O., and Elmorsy, R. E.
- Abstract
In this paper we introduce new class of q-starlike and q-convex functions of complex order involving the q-derivative operator. Morever, we find estimates on the coefficients for functions in this class. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
8. Subordination results for analytic functions associated with fractional q-calculus operators with complex order.
- Author
-
Aouf, M. K. and Mostafa, A. O.
- Abstract
Using a q-fractional calculus operators, we define the classes S α (λ , β , b , q) and G α (λ , β , b , q) of analytic functions with complex order and investigate some subordination results for these classes. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
9. Fekete–Szegö properties for quasi-subordination class of complex order defined by Sălăgean operator.
- Author
-
Aouf, M. K., Mostafa, A. O., and Madian, S. M.
- Abstract
In this paper, we introduce the class M b , λ , n q (φ , ϕ) of quasi subordinations defined by Sălăgean operator, which generalizes known classes and contains new classes. Also we will obtain the coefficient bounds for functions belonging to the class M b , λ , n q (φ , ϕ). A number of known or new results are shown to follow upon specializing the parameters involved in our main results. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
10. Nanocrystalline NiWO4-WO3-WO2.9 Composite Strings: Fabrication, Characterization and their Electrocatalytic Performance for Hydrogen Evolution Reaction.
- Author
-
Anis, Shaheen Fatima, Mostafa, Ahmad O., Hilal, Nidal, and Hashaikeh, Raed
- Subjects
HYDROGEN evolution reactions ,TUNGSTEN ,CALCINATION (Heat treatment) ,DIFFRACTION patterns - Abstract
In this study, novel nano crystalline composite strings made from mixed nickel-tungsten oxides (NiWO
4 -WO3 -WO2.9 ) have been fabricated. The NiWO4 -WO3 fibers produced by the electrospinning method were post treated in an argon atmosphere at 800 °C which yielded NiWO4 -WO3 -WO2.9 nanocrystals attached together forming a string-like structure. The presence of WO2.9 phase was confirmed by both the XRD and TEM diffraction pattern analysis. String morphology and structure were found to change with different post treatment conditions such as by changing the calcination temperature from 550 °C under oxygen to 800 °C under pure argon atmosphere. This material was investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2 SO4 and 0.1 M KOH electrolytes. These composite strings showed good electrocatalytic activity compared to the NiWO4 -WO3 fibers reported previously (Anis et al. in J. Mater. Sci. 52:7269–7281, 2017). It was concluded that the presence of WO2.9 phase increases the electrocatalytic activity of the catalyst as compared to the NiWO4 -WO3 fibers with overpotentials as low as 40 and 50 mV in 0.5 M H2 SO4 and 0.1 M KOH, respectively. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
11. Subordinating results for p-valent functions associated with the Srivastava-Saigo-Owa fractional differintegral operator.
- Author
-
Mostafa, A. O., Aouf, M. K., and Zayed, H. M.
- Abstract
In this paper, by making use of the principle of subordination, we investigate some subordination and convolution properties of certain subclasses ofp
-valent analytic functions which are defined by the Srivastava-Saigo-Owa fractional differintegral operator. [ABSTRACT FROM AUTHOR] - Published
- 2018
- Full Text
- View/download PDF
12. Inclusion relations for subclasses of multivalent functions defined by Srivastava-Saigo-Owa fractional differintegral operator.
- Author
-
Mostafa, A. O., Aouf, M. K., and Zayed, H. M.
- Abstract
The purpose of this paper is to introduce subclasses of multivalent functions by using Srivastava-Saigo-Owa fractional differintegral operator and investigate various properties for these subclasses. Also, we investigate inclusion relations involving the operator Fp,c
. [ABSTRACT FROM AUTHOR] - Published
- 2018
- Full Text
- View/download PDF
13. Multivalent functions associated with Srivastava-Saigo-Owa fractional differintegral operator.
- Author
-
Mostafa, Adela O., Aouf, Mohamed K., Zayed, Hanaa M., and Bulboacă, Teodor
- Abstract
The purpose of the present paper is to investigate some subordination and other properties of several subclasses of multivalent functions which are defined by the Srivastava-Saigo-Owa fractional differintegral operator. Inclusion relations for functions in the class Sp,λ,μ,ηm,δ,ζ(α;A,B)
and the images of these functions by the generalized Bernardi-Libera-Livingston integral operator are also considered. [ABSTRACT FROM AUTHOR] - Published
- 2018
- Full Text
- View/download PDF
14. Convolution conditions for subclasses of meromorphic functions of complex order associated with basic Bessel functions.
- Author
-
Mostafa, Adela O., Aouf, Mohamed K., Zayed, Hanaa M., and Bulboacă, Teodor
- Abstract
Making use of the operator L q , ν associated with functions of the form f ( z ) = 1 z + ∑ k = 1 ∞ a k z k − 1 , which are analytic in the punctured unit disc U * : = U ∖ { 0 } , we introduce two subclasses of meromorphic functions and investigate convolution properties and coefficient estimates for these subclasses. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
15. ON CONVOLUTION PROPERTIES FOR SOME CLASSES OF MEROMORPHIC FUNCTIONS ASSOCIATED WITH LINEAR OPERATOR.
- Author
-
MOSTAFA, A. O. and AOUF, M. K.
- Subjects
- *
MATHEMATICAL convolutions , *MEROMORPHIC functions , *VALUE distribution theory , *LINEAR operators , *OPERATOR theory , *SET theory - Abstract
In this paper, we defined two classes S*p(n, λ, A, B) and Kp(n, λ, A, B) of meromorphic p-valent functions associated with a new linear operator. We obtained convolution properties for functions in these classes. [ABSTRACT FROM AUTHOR]
- Published
- 2015
16. Mapping Properties for Convolution Involving Hypergeometric Series.
- Author
-
Aouf, M. K., Mostafa, A. O., and Zayed, H. M.
- Abstract
We introduce sufficient conditions for (Gaussian) hypergeometric functions to be in a subclass of analytic functions. In addition, we investigate several mapping properties for convolutions and integral convolutions involving hypergeometric functions. [ABSTRACT FROM AUTHOR] - Published
- 2019
- Full Text
- View/download PDF
17. Differential subordination applications to a class of meromorphic multivalent functions associated with Mittag-Leffler function.
- Author
-
Mostafa, Adela O. and El-hawsh, Ghada M.
- Published
- 2019
- Full Text
- View/download PDF
18. Bi-univalent properties for certain class of Bazilevič functions defined by convolution and with bounded boundary rotation.
- Author
-
Aouf, Mohamed K., Madian, Samar M., and Mostafa, Adela O.
- Published
- 2019
- Full Text
- View/download PDF
19. Electrospun nickel–tungsten oxide composite fibers as active electrocatalysts for hydrogen evolution reaction.
- Author
-
Anis, Shaheen Fatima, Lalia, Boor Singh, Mostafa, Ahmad O., and Hashaikeh, Raed
- Abstract
Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Novel crystalline nickel–tungsten oxide composite fibers were synthesized for the first time, to the best of our knowledge, through the electrospinning method using nickel acetate and ammonium metatungstate as precursor solutions. Fibers with five different Ni:W molar ratios, 2:1, 1:1, 1:2, 3:1 and 1:3, were prepared. After calcination, the produced fibers were composed of tungsten oxide (WO3), nickel oxide (NiO) and nickel tungstate (NiWO4). Fiber morphology and structure were studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Selected fibers were investigated for electrocatalytic hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 0.1 M KOH electrolytes. The electrospun composite fibers showed good electrocatalytic activity compared to pure NiO and WO3 fibers with an overpotential of 80 mV and 60 mV in acidic and basic media, respectively. Low Tafel slopes were also registered as 50.27 mV/dec and 41.29 mV/dec in H2SO4 and KOH, respectively. The presence of NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. [ABSTRACT FROM AUTHOR] - Published
- 2017
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.