Abstract Doping is an effective way to engineer the electronic band structure of semiconductor materials and consequently their photocatalytic activity for hydrogen generation. In this work, periodic Density Functional Theory (DFT) was employed to compare the adsorption of H2S and H2O molecules on TiO2(101) anatase surfaces compared to four transition metal-doped TiO2(101) anatase surfaces; Cr4+-TiO2, V4+-TiO2, Mn4+-TiO2, and Nb4+-TiO2. The defect formation energy, molecular adsorption energy, hydrogen splitting energies, geometrical changes, electronic structure and charge transfer characteristics were investigated to determine and compare the changes in adsorption of H2S and H2O on the pristine vs. doped surfaces. The defect formation energy calculations revealed the Nb4+-TiO2 surface resulted in the highest stability, smallest change in neighboring bond lengths and the highest dopant to surface charge transfer. However, upon H2S and H2O adsorption, the calculations concluded that the V4+-TiO2 surface resulted in the most stable structure for adsorbed H2S and lowest hydrogen splitting energy requiment compared to the other dopant metals and the lowest for H2S vs H2O, indicating its potential catalytic activity for facile dehydrogenation for industrial applications.
Last. Ying Zhou(SWPU: Southwest Petroleum University)H-Index: 52
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Abstract The options of transition metals as co-catalysts for photocatalytic H2S splitting are restricted to some noble metals and related compounds which have noticeable achievements despite their high prices. Substituting with cheap transition metals and downsizing the size to single atom level are economic ways to lower the cost. Herein, the s-triazine graphite-like carbon nitride sheet g-C3N4 (001) is chosen as the model to study the performances of 3d and 4d transition metal single atoms (T...
Last. Nageh K. Allam(The: American University in Cairo)H-Index: 36
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We report on the first fabrication of vertically-oriented niobium-zirconium oxynitride nanotube arrays and their use as an attractive and robust material for visible-light-driven water oxidation. T...
#1Aya A. Saleh(The: American University in Cairo)H-Index: 1
#2Mahmoud M. Farag(The: American University in Cairo)H-Index: 15
Last. Nageh K. Allam(The: American University in Cairo)H-Index: 36
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Abstract We report on the optimized fabrication of ultrathin wall nanotubes grown on Ti–Nb alloy via anodization in organic-based electrolytes. The nanotubes are vertically aligned with wall thicknesses of 5–8 nm, diameters of 180–200 nm, and lengths of 2–2.8 μm. Raman spectroscopy and glancing angle x-ray diffraction (GAXRD) measurements indicated the formation of composite oxides of anatase TiO2 and monoclinic Nb2O5. The composite oxides showed better stability at elevated temperatures up to 6...
Heterogenous electrocatalysts based on transition metal sulfides (TMS) are being actively explored in renewable energy research because nanostructured forms support high intrinsic activities for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, it is described how researchers are working to improve the performance of TMS-based materials by manipulating their internal and external nanoarchitectures. A general introduction to the water-splitting reaction is in...
#1Menna M. Hasan(The: American University in Cairo)H-Index: 3
#2Sarah A. Tolba(The: American University in Cairo)H-Index: 5
Last. Nageh K. Allam(The: American University in Cairo)H-Index: 36
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There is a growing need for new techniques to synthesize metallic copper nanoparticles due to their remarkable use in many advanced technologies. Herein, a novel method to synthesize stable and nonagglomerated zero-valent copper nanoparticles (ZVCNPs) via the in situ formation of reduced graphene oxide (rGO) during the electrospinning process in the presence of polyvinylpyrrolidone as a carbon source is presented. X-ray diffraction, Raman spectroscopy, electron paramagnetic resonance, transmissi...
Anatase titanium oxide is important for its high chemical stability and photocatalytic properties, however, the latter are plagued by its large band gap that limits its activity to only a small percentage of the solar spectrum. In that respect, straining the material can reduce its band gap increasing the photocatalytic activity of titanium oxide. We apply density functional theory with the introduction of the Hubbard + U model, to investigate the impact of stress on the electronic structure of ...
#1Xiangyu Guo(Huada: Beijing University of Chemical Technology)H-Index: 7
#2Shangguo Liu(Huada: Beijing University of Chemical Technology)H-Index: 3
Last. Shiping Huang(Huada: Beijing University of Chemical Technology)H-Index: 23
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Abstract We present a comprehensive understanding of sing Ru atom supported on defective graphene for water splitting using density functional theory calculations and microkinetic analysis. The structural and electronic properties of Ru atom supported single vacancy graphene (SVG), double vacancy graphene (DVG) and Stone-Wales graphene (SWG) are systematically investigated. We find that the Ru atom can be trapped effectively by the defects on each defective graphene surfaces. The binding strengt...
Last. Nageh K. Allam(The: American University in Cairo)H-Index: 36
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Black TiO2 is being widely investigated due to its superior optical activity and potential applications in photocatalytic hydrogen generation. Herein, the limitations of the hydrogenation process of TiO2 nanostructures are unraveled by exploiting the fundamental tradeoffs affecting the overall efficiency of the water splitting process. To control the nature and concentration of defect states, different reduction rates are applied to sub-100 nm TiO2 nanotubes, chosen primarily for their superiori...
Last. S.Z. Baykara(YTU: Yıldız Technical University)H-Index: 16
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Abstract Hydrogen production via catalytic thermal decomposition of hydrogen sulfide (H2S) was studied experimentally by synthesizing, characterizing and testing perovskite type catalysts; AxAʹ(1−x)ByBʹ(1−y)O3. In the formulation, A and Aʹ represented La and Sr respectively, B was chosen as Cr, and Bʹ was either Co or Mo or V. The subscript x of the perovskite structure was 0.9 and y values were 1, 0.75, 0.5 and 0.25. Catalytic thermal splitting of H2S was conducted in a continuous flow quartz r...
Last. Nageh K. Allam(The: American University in Cairo)H-Index: 36
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Abstract The activity and stability of the anode biofilm control the produced power by microbial fuel cells (MFCs). In this study, 3D nanoporous stainless steel (SS) was used as an anode material in MFCs to enhance both the biofilm growth and its adhesion to the support electrode, which would improve the catalytic activity and stability of MFCs anode biofilm. The effect of varying the annealing atmosphere on the SS performance was studied and correlated with the change in the oxidation states of...
Abstract Designing next-generation advanced electrode materials by engineering their structural and compositional features can provide a feasible strategy to enhance the electrochemical performance of energy conversion devices. In this study, the rational pathway to design and fabricate nanotube arrays of titanium manganese phosphide via etching of titanium-manganese alloy followed by plasma phosphidation in PH3 environment is presented and discussed. The structural and elemental analyses of the...
Last. Nageh K. Allam(The: American University in Cairo)H-Index: 36
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Abstract In this study, a considerable effort has been devoted for the synthesis of Ge-doped ZnO nanorods on FTO as an efficient and robust photoanode material for solar water splitting. A unique, optimized, and ultra-rapid fabrication method to produce uniform nanorods (30–70 nm in diameter) has been demonstrated using radio frequency sputtering followed by electrochemical anodization. The effect of Ge doping on the conductivity, charge carrier concentration, optical, and photoelectrochemical p...