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Article
Publication date: 3 July 2017

Behnam Seyyedi

The purpose of this paper is to introduce bio-inspired FeN4-S-C black nano-electrocatalyst for the oxygen reduction reaction (ORR) in an alkaline medium. The FeN4-S-C…

Abstract

Purpose

The purpose of this paper is to introduce bio-inspired FeN4-S-C black nano-electrocatalyst for the oxygen reduction reaction (ORR) in an alkaline medium. The FeN4-S-C derived without pyrolysis of precursors in high temperature is recognized as a new electrocatalyst for the ORR in an alkaline electrolyte. For the proper design of bio-inspired nano-electrocatalyst for the ORR performance, chlorinated iron (II) phthalocyanine nanoparticles were used as templates for achieving the active sites in aqueous KOH by rotating disk electrode methods. The most active FeN4-S-C catalyst exhibited a remarkable ORR activity in the alkaline medium. The objectives of this paper are to investigate the possibility of nanoscale particles size (˜5nm) of electrocatalyst, to achieve four-electron transfer mechanism and to exhibit much superior catalytic stability in measurements. This paper will shed light on bio-inspired FeN4-S-C materials for the ORR catalysis in alkaline fuel cells.

Design/methodology/approach

The paper presents a new bio-inspired nano-electrocatalyst for the ORR, which has activity nearby platinum/carbon electrocatalyst. Chlorinated iron phthalocyanine nanoparticles have been used as FeN4 template, which is the key point for the ORR. Bio-inspired nano-electrocatalyst has been fabricated using chlorinated iron phthalocyanine, sodium sulphide and carbon black.

Findings

The particles’ size was 5 nm and electron transfer number was 4.

Research limitations/implications

The catalyst that is used in this method should be weighed carefully. In addition, the solvent should be a saturated solution of NaCl in water.

Practical implications

The method provides a simple and practical solution to improving the synthesis of iron-based catalyst for ORR.

Originality/value

The method for the synthesis of bio-inspired electrocatalyst was novel and can find numerous applications in industries, especially as ORR non-precious metal catalyst.

Details

Pigment & Resin Technology, vol. 46 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 26 January 2021

Ibrahim A. Amar and Mohammed M. Ahwidi

This paper aims to investigate the electrocatalytic activity of CoFe1.9Mo0.1O4-Ce0.8Gd0.18Ca0.02O2-δ composite (CFMo-CGDC) for the direct synthesis of ammonia from H2O and…

Abstract

Purpose

This paper aims to investigate the electrocatalytic activity of CoFe1.9Mo0.1O4-Ce0.8Gd0.18Ca0.02O2-δ composite (CFMo-CGDC) for the direct synthesis of ammonia from H2O and N2 under atmospheric pressure.

Designs

CoFe1.9Mo0.1O4 nanoparticles (CFMo NPs) were synthesized via a sol-gel method. CFMo NPs were characterized using X-ray diffraction (XRD), Brunauer–Emmet–Teller (BET) specific surface area measurement and scanning electron microscope (SEM). Double-chamber reactor was used to synthesize ammonia using H2O and N2 as precursors. The factors affecting the ammonia formation rate (applied voltage and temperature) were studied.

Findings

CoFe1.9Mo0.1O4 nanoparticles (CFMo NPs) were synthesized via a sol-gel method. CFMo NPs were characterized using XRD, Brunauer–Emmet–Teller (BET) specific surface area measurement and SEM. Double-chamber reactor was used to synthesize ammonia using H2O and N2 as precursors. The factors affecting the ammonia formation rate (applied voltage and temperature) were studied.

Originality/value

The usage of CFMo-CGDC composite as an electrocatalyst for the synthesis of ammonia directly from H2O and N2.

Details

World Journal of Engineering, vol. 18 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

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Article
Publication date: 10 December 2019

Zeinab Abdel Hamid, H.B. Hassan and Mohamed Sultan

The improvement of the hydrogen evolution reaction (HER) performance requires more efficient and inexpensive electrocatalysts. The purpose of this study is to prepare Ni-W…

Abstract

Purpose

The improvement of the hydrogen evolution reaction (HER) performance requires more efficient and inexpensive electrocatalysts. The purpose of this study is to prepare Ni-W and Ni-W-P thin films using the electrodeposition technique using a pulse current and investigate their behaviors toward HER in an acidic solution.

Design/methodology/approach

The aim is to prepare Ni-W and Ni-W-P films by the electrodeposition technique using a pulse current and estimate their performance for the HER. The surface morphologies and chemical compositions of the deposited films were assessed using scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. Linear sweep voltammetry, chronoamperometry, Tafel plots and electrochemical impedance spectroscopy were used to evaluate the prepared electrodes toward the hydrogen evolution process.

Findings

The main conclusion is that the surface morphology of Ni–W deposited film is a crystalline structure, while that of Ni-W-P deposit is an amorphous structure. HER activity on Ni-W electrodes increases with decreasing the Wt.% of W to 7.83 Wt.% in the prepared electrodes. In addition, the presence of P enhances HER activity, which increases with increasing the Wt.% of P in the prepared Ni-W-P electrodes. Both Ni-W (7.83 Wt.% W) and Ni-W-P (20.34 Wt.% P), which have been prepared at 8 A dm−2 display the best performance toward HER compared to the other prepared electrodes. They exhibit high catalytic activities toward HER, which is evidenced by high hydrogen evolution current density values of 9.52 and 33.98 mA cm−2, low onset potentials of −0.73 and −0.63 V, low Tafel slopes of −125 mV/dec, high exchange current densities of 0.058 and 0.20 mA cm−2, low charge transfer resistances (Rct) of 226.28 and 75.8 ohm·cm2 for Ni-W (7.83  Wt.% W) and Ni-W-P (20.34  Wt.% P), respectively; moreover, they exhibited considerable stabilities too.

Originality/value

The results presented in this work are an insight into understanding the performance of the prepared Cu electrodes coated by Ni-W and Ni-W-P films toward HER. In this work, a consistent assessment of the results achieved on laboratory scale has been conducted.

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Article
Publication date: 5 January 2015

H.Y. Zhang, H.J. Niu, Y.M. Wang, C. Wang, X.D. Bai, , S. Wang and Wen Wang

The purpose of this paper was to provide a simple method for the preparation of carbon nanotubes (CNTs) by pyrolysing sunflower seed hulls and sago and to evaluate the…

Abstract

Purpose

The purpose of this paper was to provide a simple method for the preparation of carbon nanotubes (CNTs) by pyrolysing sunflower seed hulls and sago and to evaluate the application of such CNTs in supercapacitors.

Design/methodology/approach

The CNTs were obtained by pyrolysing sunflower seed hulls and sago at 800°C. The prepared CNTs were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammograms, galvanostatic charge and discharge and electrochemical impedance spectra methods.

Findings

The CNTs had large surface areas as determined by the methylene blue method and the Brunauer – Emmett – Teller method. And the CNTs that were prepared by pyrolysing the natural sunflower seed hulls (denoted as CNTs-1) and sago (denoted as CNTs-2) had capacitances of 86.9 F/g and 26.7 F/g, respectively.

Research limitations/implications

The capacitances of CNTs can be further improved.

Practical implications

The exceptional electronic and mechanical properties of CNTs prepared lend the CNTs to diverse applications including electrocatalysts, hydrogen storage, photovoltaic devices actuators, energy storage, field-emitting flat panel displays and composites.

Originality/value

Currently, CNTs have not yet been used in the industry at a mass production scale due to high costs associated. The outcomes of the study reported in this article could provide a convenient method in aid of industrialisation of the production of CNTs.

Details

Pigment & Resin Technology, vol. 44 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 6 March 2017

Behnam Seyyedi

The paper introduces a microwave and electrochemical-assisted method for synthesis of chlorine-derived iron phthalocyanine pigment and oxygen reduction reaction catalyst…

Abstract

Purpose

The paper introduces a microwave and electrochemical-assisted method for synthesis of chlorine-derived iron phthalocyanine pigment and oxygen reduction reaction catalyst nanoparticles. The aims of this study are to investigate the possibility of nano-scale particle size (<35 nm), high-efficiency product reaction, remove acidic wastewater, time optimization and maximize number of chlorine on aromatic rings.

Design/methodology/approach

The paper presents a combined synthesis technique, which does not have the problems of the conventional methods. Chlorinated iron phthalocyanine nanoparticles have been fabricated using phthalic anhydride, urea (high purity), electrochemical-generated iron (II) cations and microwave irradiation as promoter. The approach yields a product of high quality, uniform particle size distribution and high efficiency and that was environment-friendly.

Findings

The particle size and time needed for the production of chlorinated iron phthalocyanine were about 35 nm and 7 min, respectively.

Research limitations/implications

The catalyst, that is used in this method, should be weighed carefully. In addition, the solvent should be a saturated solution of NaCl in water.

Practical implications

The method provides a simple and practical solution to improving the synthesis of an iron-based catalyst for oxygen reduction reaction.

Originality/value

The combined method for synthesis of chlorinated iron phthalocyanine was novel and can find numerous applications in the industry, especially as an oxygen reduction reaction non-precious metal catalyst.

Details

Pigment & Resin Technology, vol. 46 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 1 April 1987

City Technology is one company that seems to know how to run a sensor manufacturing business, as Stephen McClelland explains.

Abstract

City Technology is one company that seems to know how to run a sensor manufacturing business, as Stephen McClelland explains.

Details

Sensor Review, vol. 7 no. 4
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 15 June 2010

Kaushik Alayavalli and David L. Bourell

The purpose of this paper is to produce electrically conductive, fluid impermeable graphite bipolar plates for a direct methanol fuel cell, using indirect selective laser…

Abstract

Purpose

The purpose of this paper is to produce electrically conductive, fluid impermeable graphite bipolar plates for a direct methanol fuel cell, using indirect selective laser sintering (SLS) and suitable post processing techniques.

Design/methodology/approach

Bipolar plates are made by the indirect SLS of graphite powder and phenolic resin mixture. The phenolic resin binder is then burnt off at a high temperature in a vacuum furnace to produce a 100 per cent carbon part. This brown part is then infiltrated using a low‐viscosity (∼5‐10  cps) cyanoacrylate to seal up the open pores, rendering the plates fluid impermeable.

Findings

It has been found that the electrical conductivity increases significantly (> 220 S/cm) with a corresponding increase in pyrolyzing temperature which correlates well with literature on the carbonization of phenol formaldehyde resins. The cyanoacrylate infiltrated parts tested under fluid pressure demonstrated no leakage through the plate, indicating full closure of open porosity.

Originality/value

This work demonstrates the capability of the SLS process to produce working bipolar plates with complex flow field designs that can be tested to verify its efficacy in a working fuel cell, thereby saving time and cost in machining natural graphite.

Details

Rapid Prototyping Journal, vol. 16 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 10 May 2021

A. Bahrawy, Mohamed El-Rabiei, Hesham Elfiky, Nady Elsayed, Mohammed Arafa and Mosaad Negem

The commercial stainless steels have been used extensively in the biomedicine application and their electrochemical behaviour in the simulated body fluid (SBF) are not…

Abstract

Purpose

The commercial stainless steels have been used extensively in the biomedicine application and their electrochemical behaviour in the simulated body fluid (SBF) are not uncovered obviously. In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys (x = 4, 8, 10 and 14) has been studied. This study aims to evaluate the rate of corrosion and corrosion resistance of some Fe–Cr–Ni alloys in SBF at 37°C.

Design/methodology/approach

In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys has been studied using open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization in the SBF at 37°C and pH 7.4 for a week. Also, the surface morphology of the four alloys was investigated using scanning electron microscopy, elemental composition was obtained via energy dispersive spectroscopy and the crystal lattice structure of Fe–17Cr–xNi alloys was obtained using X-ray diffraction technique. The chemical structure of the protective oxide film has been examined by X-ray photoelectron spectroscopy (XPS) and metals ions released into the solution have been detected after different immersion time using atomic absorption spectroscopy.

Findings

The results revealed that the increase of the Ni content leads to the formation of the stable protective film on the alloys such as the Fe–17Cr–10Ni and Fe–17Cr–14Ni alloys which possess solid solution properties. The Fe–17Cr–14Ni alloy displayed highest resistance of corrosion, notable resistance for localized corrosion and the low corrosion rate in SBF because of the formation of a homogenously protective oxide film on the surface. The XPS analysis showed that the elemental Fe, Cr and Ni react with the electrolyte medium and the passive film is mainly composed of Cr2O3 with some amounts of Fe(II) hydroxide at pH 7.4.

Originality/value

This work includes important investigation to use commercial stainless steel alloys for biomedical application.

Details

Anti-Corrosion Methods and Materials, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 12 March 2021

Hamed Dabaghi, Seyed Mohammad Tabataba’i-Nasab and Saeid Saieda Ardakani

The purpose of this paper is to focus on the emerging phenomenon of medical tourism in the context of Iran from a customer experience management perspective and benchmark…

Abstract

Purpose

The purpose of this paper is to focus on the emerging phenomenon of medical tourism in the context of Iran from a customer experience management perspective and benchmark of their judgment including positive or negative, of the experience they have achieved of the Iranian health (medical) experience (CE) and suggest scenarios for the improvement of the Iranian customer experience management (CEM).

Design/methodology/approach

The research methodologies and research methods that are used in this descriptive-analytical research are based on an inspection of the remarkable literature related to medical tourism and customer experience management. The data gathering instrument is a researcher-made questionnaire based on the variables in the conceptual model extracted from the research literature. The study was conducted from May to August 2019. The population cohort of this study was the foreign patients calling selected Iranian hospitals and the sampling method was a purposive and snowball sample of prospective medical tourists. As the study was conducted throughout Iran, some important hospitals in Iran were selected by stratified sampling Yang et al. (2020b). The sample size and data saturation were 500 participants Lv and Song (2019). The collected data using the questionnaire were analyzed by SPSS software and statistical tests.

Findings

According to the results, the customer experience management statistical significance in the task aspect is (p = 0.0523), in the mechanical aspect is (p = 0.0563), in the human aspect is (p = 0.0544). The study showed positive customer experience among the patients who had been treated in the Iranian hospitals.

Originality/value

There is a lack of study that focuses on medical tourism and customer experience management in Iran. Therefore, based on the results of this study, the experience of medical tourists in Iran proved to be positive and satisfying. As little research has been conducted in the area of customer experience management (CEM) in Iranian medical tourism, future researchers can use these valuable results precisely and in more detail to benchmark more accurately the customer experience in all areas of medical and health tourism and other research areas in different aspects of CEM in Iran.

Details

Journal of Islamic Marketing, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1759-0833

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Article
Publication date: 14 December 2020

Mostafa Safdari Shadloo

Convection is one of the main heat transfer mechanisms in both high to low temperature media. The accurate convection heat transfer coefficient (HTC) value is required for…

Abstract

Purpose

Convection is one of the main heat transfer mechanisms in both high to low temperature media. The accurate convection heat transfer coefficient (HTC) value is required for exact prediction of heat transfer. As convection HTC depends on many variables including fluid properties, flow hydrodynamics, surface geometry and operating and boundary conditions, among others, its accurate estimation is often too hard. Homogeneous dispersion of nanoparticles in a base fluid (nanofluids) that found high popularities during the past two decades has also increased the level of this complexity. Therefore, this study aims to show the application of least-square support vector machines (LS-SVM) for prediction of convection heat transfer coefficient of nanofluids through circular pipes as an accurate alternative way and draw a clear path for future researches in the field.

Design/methodology/approach

The proposed LS-SVM model is developed using a relatively huge databank, including 253 experimental data sets. The predictive performance of this intelligent approach is validated using both experimental data and empirical correlations in the literature.

Findings

The results show that the LS-SVM paradigm with a radial basis kernel outperforms all other considered approaches. It presents an absolute average relative deviation of 2.47% and the regression coefficient (R2) of 0.99935 for the estimation of the experimental databank. The proposed smart paradigm expedites the procedure of estimation of convection HTC of nanofluid flow inside circular pipes.

Originality/value

Therefore, the focus of the current study is concentrated on the estimation of convection HTC of nanofluid flow through circular pipes using the LS-SVM. Indeed, this estimation is done using operating conditions and some simply measured characteristics of nanoparticle, base fluid and nanofluid.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

Keywords

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