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Abdelkareem, Mohammad Ali,Sayed, Enas Taha,Mohamed, Hend Omar,Obaid, M.,Rezk, Hegazy,Chae, Kyu-Jung Elsevier 2020 Progress in energy and combustion science Vol.77 No.-
<P><B>Abstract</B></P> <P>Fuel cells are electrochemical devices that convert chemical energy directly into electrical energy with high efficiency. The high cost of platinum catalysts and sluggish reaction kinetics are the main challenges in the development of low-temperature fuel cells. Although significant efforts have been made to prepare effective non-precious-metal-based oxygen reduction reaction (ORR) catalysts, suitable anodic catalysts are still far from realization. The reported onset potential of a nonprecious anodic catalyst toward low-molecular-weight hydrocarbons, such as methanol, ethanol, and urea, in alkaline media is approximately 0.35 V (vs. Ag/AgCl), which is far from the theoretical potentials of −0.61, −0.54, and −0.55 V (vs. Ag/AgCl), respectively. Therefore, some researchers concluded that nonprecious anodic catalysts are not practical, taking into account the ORR potential of 0.2 V (vs. Ag/AgCl) in alkaline media. Recently, however, several reports demonstrated an open-circuit voltage (OCV) of more than 0.8 V using non-precious-metal-based anodic catalysts, which contradicts expectations. Therefore, to answer these conflicting claims, this review intensively discusses the possibility of using nonprecious metals, for example Ni-based catalysts, for actual electricity generation in direct (methanol, ethanol, and urea) fuel cells, and the different methods applied to achieve the highest values of OCV. Also, the progress done in the preparation of nonprecious anodic catalysts is reviewed. Finally, conclusions and recommendations to prepare durable and active fuel cells using non-precious-metal-based anodic catalysts are presented.</P>
Barakat, N.A.M.,Abdelkareem, M.A.,Yousef, A.,Al-Deyab, S.S.,El-Newehy, M.,Kim, H.Y. Pergamon Press ; Elsevier Science Ltd 2013 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.38 No.8
Cd-doped Cobalt nanoparticles encapsulated in graphite shell have been synthesized using a simple sol-gel technique. Typically, a sol-gel composed of cadmium acetate, cobalt acetate and poly(vinyl alcohol) has been prepared based on the polycondensation property of the acetates. The utilized physiochemical characterizations affirmed that drying, grinding and calcination in Ar atmosphere of the prepared gel leads to produce Cd-doped Co nanoparticles encapsulated in a thin graphite layer. The prepared nanoparticles revealed good electroactivity towards methanol electrooxidation. High current density (70 mAcm<SUP>-2</SUP>) and considerably low onset potential (~600 mV vs. NHE) were obtained. Moreover, because of the graphite shell, good stability was observed. Considering that the introduced nanoparticles composed of nonprecious metals and the obtained electrochemical results are satisfactory, the introduced study might open new avenues for the cobalt-based nanostructures to be used as novel effective electrocatalysts in the fuel cells applications.
Barakat, Nasser AM,Abdelkareem, Mohammad Ali,El-Newehy, Mohamed,Kim, Hak Yong Springer 2013 Nanoscale research letters Vol.8 No.1
<P>In this study, the influence of the morphology on the electrocatalytic activity of nickel oxide nanostructures toward methanol oxidation is investigated. Two nanostructures were utilized: nanoparticles and nanofibers. NiO nanofibers have been synthesized by using the electrospinning technique. Briefly, electrospun nanofiber mats composed of polyvinylpyrolidine and nickel acetate were calcined at 700°C for 1 h. Interestingly, compared to nanoparticles, the nanofibrous morphology strongly enhanced the electrocatalytic performance. The corresponding current densities for the NiO nanofibers and nanoparticles were 25 and 6 mA/cm<SUP>2</SUP>, respectively. Moreover, the optimum methanol concentration increased to 1 M in case of the nanofibrous morphology while it was 0.1 M for the NiO nanoparticles. Actually, the one-dimensional feature of the nanofibrous morphology facilitates electrons' motion which enhances the electrocatalytic activity. Overall, this study emphasizes the distinct positive impact of the nanofibrous morphology on the electrocatalytic activity which will open a new avenue for modification of the electrocatalysts.</P>
Mohamed, Hend Omar,Abdelkareem, Mohammad Ali,Park, Mira,Lee, Jinpyo,Kim, Taewoo,Prasad Ojha, Gunendra,Pant, Bishweshwar,Park, Soo-Jin,Kim, HakYong,Barakat, Nasser A.M. Elsevier 2017 International journal of hydrogen energy Vol.42 No.38
<P><B>Abstract</B></P> <P>This study investigates the effect of cation exchange membrane (CEM) diffusion layers on cathode potential behavior in microbial fuel cells based on a cobalt electrodeposited anode that works in actual industrial wastewater. The structural properties of the modified anode materials were evaluated using scanning electron microscopy (SEM), which showed a strong and clear biofilm layer on the anode surface. Additionally, the structural properties of the utilized cathode materials were evaluated using energy dispersive X-ray (EDX) spectrometry and field emission scanning electron microscopy (FE-SEM) techniques, which confirmed the transfer of cobalt ions through the CEM to the cathode surface. Finally, the performance of the modified anode material with various CEMs as diffusion layers was investigated in air-cathode microbial fuel cells. The results indicate that the metal electrodeposition strategy, which utilizes multiple CEM layers, enhanced the power and current generation by 498.2 and 455%, respectively. Moreover, the Columbic efficiency (CE) increased by 77%, 154.5%, and 232% for the MFC with one, two and three CEM layers, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Multilayer-cation exchange membrane enhanced cathode potential of MFC. </LI> <LI> Electro deposition of cobalt significantly improved the anode activity. </LI> <LI> Multilayer CEM and Co deposition increased power by 498.2% and current by 455%. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Mohamed, Hend Omar,Abdelkareem, Mohammad Ali,Obaid, M.,Chae, Su-Hyeong,Park, Mira,Kim, Hak Yong,Barakat, Nasser A.M. Elsevier 2017 Chemical engineering journal Vol.326 No.-
<P><B>Abstract</B></P> <P>A novel nanoflakes of cobalt sheathed with cobalt oxide is electrodeposited on four different carbonaceous anodes; carbon cloth (CC), carbon paper (CP) graphite (G) and activated carbon (AC), to introduce as high-performance anodes of microbial fuel cell (MFC). Interestingly, characterizations results indicated that novel metallic nanoflakes that sheathed by a thin layer of cobalt oxide were formed on the surface of the different anode materials. Moreover, using a simple and effective electrodeposition technique for fabricating of cobalt/cobalt oxide nanoflakes is introduced to overcome the hydrophobicity and the interfacial electron transfer of the anodes. The thin layer of cobalt/cobalt oxide nanoflakes significantly enhanced the microbial adhesion, the wettability of the anode surface and decrease the electron transfer resistance. Alternatively, the toxicity risk of the pure cobalt is overcome by the cobalt oxide layer. The application of the modified anodes in an air-cathode MFCs fed by industrial wastewater resulted in a significant improving in cell performance for the different anode materials. Where, the observed increasing in the power was 103, 137, 173 and 71% for the CC, CP, G and AC electrodes, respectively. This proposed treatment technique represented a high-performance, excellent microbial adhesion, easy fabrication and scale-up anodes for MFC.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cobalt oxides-sheathed cobalt nano flakes was deposited on anodes using electrodeposition. </LI> <LI> The modified anodes were used in MFC to treat the wastewater and produce energy. </LI> <LI> The modified anodes shows promising results in single air-cathode MFC. </LI> <LI> The results of the modified anodes were strongly enhanced compared to the pristine anodes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Ammonium phosphate as promised hydrogen storage material
Barakat, N.A.M.,Ahmed, E.,Abdelkareem, M.A.,Farrag, T.E.,Al-Meer, S.,Al-Deyab, S.,Elsaid, K.,Nassar, M.M. Pergamon Press ; Elsevier Science Ltd 2015 International journal of hydrogen energy Vol.40 No.32
Most of the reported hydrogen storage materials are either expensive or based on synthetically complicated compounds. Ammonium phosphates are cheap and available product; it is being used as fertilizer. These compounds could be utilized as hydrogen storage materials. Stoichiometrically, mono-, di- and tri-ammonium phosphate can lead to evolve 3.875, 7.867 and 11.903 hydrogen equivalent, respectively. Using Pt/C (20 wt %) leads to produce 17.28, 11.35 and 10.15% from the equivalent hydrogen in the mono-, di- and tri-ammonium phosphate, respectively. Analyzing the obtained gases by GC confirms evolution of pure hydrogen. Moreover, ion chromatography detects and ions in the liquid which indicates hydrolysis of the ammonium phosphate. Ni/C and Co/C NPs can be exploited as catalysts; Ni/C containing 20 wt% metal reveals comparable results to Pt/C. Overall, this study opens promising avenue to develop new catalysts to enhance the hydrolysis of ammonium phosphate to produce hydrogen. Comparing to the reported hydrogen storage materials, ammonium phosphates possess comparable hydrogen content 97.28, 118.3 and 115.72 kg/m<SUP>3</SUP> for mono-, di- and tri-ammonium phosphate, respectively which is very close to the MgH<SUB>2</SUB> (115.5 kg/m<SUP>3</SUP>) and not so far from ammonia borane (148.2 kg/m<SUP>3</SUP>). However, in contrast to these compounds, hydrogen can be released from the introduced storage materials by hydrolysis only using the proper catalyst. Furthermore, the hydrolysis process results in producing different acids; nitrous, nitric and phosphoric acid which should be considered in the reactor construction precautions.
Yeast Extract as an Effective and Safe Mediator for the Baker’s-Yeast-Based Microbial Fuel Cell
Sayed, Enas Taha,Barakat, Nasser A. M.,Abdelkareem, Mohammad Ali,Fouad, H.,Nakagawa, Nobuyoshi American Chemical Society 2015 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.54 No.12
<P>Although utilizing the exogenous mediators distinctly enhances the microbial fuel cell (MFC) performance, possibility of microorganisms’ toxicity, environmental aspect and cost are the main dilemmas facing wide applications. Therefore, successful applying of the yeast extract as a mediator in the baker’s-yeast-based (<I>Saccharomyces cerevisiae</I>-based) MFCs would be of great interest as it will overcome all the aforementioned problems. The influence of the yeast extract addition was investigated based on the yeast cell adhesion on the surface of plain and gold-sputtered carbon paper anodes. In the case of plain carbon paper, the addition of the yeast extract considerably enhanced the performance of the yeast-based MFC, which can be attributed to the yeast extract role as growth media or as a mediator; the current and power densities increased from 94 to 190 mA/cm<SUP>2</SUP> and from 12.9 to 32.6 mW/cm<SUP>2</SUP>, respectively. However, compared with the plain carbon paper, in the case of gold-sputtered anode the performance significantly increased with yeast extract addition, whereas it drastically decreased without yeast extract; the current and power densities increased from 25 to 300 mA/cm<SUP>2</SUP> and from 2 to 70 mW/cm<SUP>2</SUP>, respectively. The obtained results indicated that yeast extract can be exploited as an effective mediator in the <I>Saccharomyces cerevisiae</I>-based MFCs.</P>