A variable amount of 0. Energy dispersive spectrometry EDS -line scanning and energy-filtered transmission electron microscopy EFTEM -elemental mapping analyses were carried out to probe the spatial elemental distributions of the hybrid materials.
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The local structures of the nanohybrids were studied using X-ray absorption spectroscopy XAS. The electrochemical measurements were performed at room temperature using an IVIUM analyzer with a typical three-electrode cell. A rotating ring-disk electrode-3A ALS was used as a rotator. A Pt wire and saturated calomel electrode were used as the counter electrode and reference electrode, respectively.
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The current density j was calculated from the ratio of the current over the surface area of the GC 0. The dependence of the charging current density on the scan rate was measured by cyclic voltammetry CV in the potential range from 0. RHE to cover the open circuit potential of 1. Electrochemical impedance spectroscopy EIS data were collected at 1. We consider the catalytically active site as the deprotonated oxygen atom on the LDH surface As shown in Fig. Hybridization with RuO 2 makes the third step R3 the most energetically unfavorable step with a threshold energy of 1.
To quantify the amount of charge transfer upon hybridization, we further performed a Bader charge analysis for the NCR nanohybrid, showing that 0. It was also found that the deprotonated oxygen atom which serves as the catalytically active center of Ni—Co-LDH loses the most charge 0. Atoms in the structure are colored by white for H, red for O, brown for Ni, green for Co, and navy for Ru. As plotted in Fig. The NCR nanohybrids show house-of-cards-type stacking structures, reflecting the creation of mesopores upon hybridization.
The interfacial charge transfer between the hybridized components was experimentally verified with a surface-sensitive XPS technique. Generally, there are many factors affecting the OER activity of inorganic solids, such as the crystal structure, electronic structure, particle size, and degree of hydration 43 , The OER catalytic kinetics of the present nanohybrids was also examined by calculating the Tafel slope.
The electrochemically active surface area ECSA was also estimated from the plot of the charging current versus scan rate measured by CV, and the slope of this plot is equivalent to twice that of the ECSA. As shown in the EIS data in Fig. Among the present materials, NCR10 shows the smallest semicircle with the fastest electron transfer rate and smallest R ct. Since the R ct value corresponds to the electrochemical impedance for ion migration into the interfacial region near electrochemically active sites of electrocatalysts during the OER process, this parameter is dependent on both the diffusion rate of the reactant ions into the interfacial region and the electrical conductivity of the electrocatalyst.
The content of electrocatalytically active LDH NSs has a significant influence on the R ct because promotion of the OER process will increase the ion diffusion rate into the interfacial region of the electrochemically active sites by enhancing the consumption of reactant ions. Additionally, the content of highly conductive RuO 2 NSs also affects the R ct value by increasing the electrical conductivity of the NCR electrocatalyst. As plotted in the chronopotentiometry data in Fig.
Hybridization with highly conductive RuO 2 NSs increases the electrical conductivity of the hybridized material, resulting in a decrease in the charging effect and an improvement in the electrochemical stability upon hybridization In addition, the decreased aggregation of LDH crystals and formation of a porous stacking structure upon hybridization with RuO 2 NSs can also contribute to the enhanced electrochemical stability of the NCR nanohybrids 46 , The present findings clearly demonstrate the high efficiency of RuO 2 NSs as an additive to optimize the electrocatalytic performance of LDH materials.
As shown in the LSV curves in Fig. According to the EIS analysis Fig. The present experimental findings provide strong evidence for the universal merit of RuO 2 NSs as an additive for exploring novel, efficient OER electrocatalysts in terms of strong electronic coupling with inorganic electrocatalysts and the resulting improvement in RDS kinetics.
The combination theoretical and experimental study presented here clearly demonstrates that kinetic control of the RDS of an electrocatalytic reaction can provide a rational method to explore high-performance OER electrocatalysts with a remarkable decrease in overpotentials. Based on this theoretical calculation, highly efficient OER activities with remarkably lower overpotentials and excellent electrochemical stabilities can be achieved by intimate hybridization between electrocatalytically active LDH NSs and electron-withdrawing RuO 2 NSs.
Nanoscale hybridization between exfoliated LDH and RuO 2 NSs can be easily achieved by an electrostatically derived self-assembly process because of their opposite surface charges. We determined that the theoretical comparison of a single LDH layer versus an LDH—RuO 2 bilayer corresponding to the case when every LDH layer develops an interaction with RuO 2 resulted in a more drastic change in the calculated overpotential than the experimental values.
The present electrochemical results clearly demonstrate the effectiveness of hybridization with electron-withdrawing inorganic NSs in remarkably improving the electrocatalytic functionality of polar, inorganic solids. Controlling the RDS via hybridization with a small amount of electron-withdrawing RuO 2 NSs provides a novel, rational method to explore economically feasible efficient electrocatalysts. The very low Ru content of the present nanohybrid provides this material with a high level of economic feasibility over that of conventional RuO 2 -based OER electrocatalysts.
It is worthwhile to mention that despite the rarity of Ru, the price of Ru is still 12 times cheaper than that of Ir, which is also utilized as an OER electrocatalyst 48 , underscoring the validity of the present nanohybrid as an economically feasible electrocatalyst. Considering the fact that the 2D morphology of inorganic NSs provides effective anchoring sites for diverse inorganic electrocatalysts, the present synthetic strategy with electron-withdrawing or electron-donating inorganic NSs will evoke a great deal of research on the development of new, high-performance, hybrid electrocatalysts.
A high flexibility in the compositional control of inorganic NSs via cation- and anion-substitution allows us to optimize the electronic structure and ability to accept or donate electron density of hybridized electrocatalysts Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Su, D. Edge Science Fiction and Fantasy Publishing. Aurealis Awards. Locus Online.
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Archived from the original on Categories : births 21st-century Australian novelists Australian male novelists Australian science fiction writers Living people 21st-century Australian male writers Australian writer stubs. Namespaces Article Talk. Views Read Edit View history. Baizhigitova, Nurziya R. Akmukhanova, Roman A. Sidorov, Maria A. Sinetova, Dmitry A.
Among these strains, C. CH 4 was the predominant biogas composition, while no H 2 was observed in the sole glycerol waste fermentation. H 2 production was predominantly detected in the combined decanter cake fermentation. The presence of the anaerobic sludge appeared to promote only methanogenesis resulting shorter fermentation period, lower glycerol waste utilization and biogas production potential H max.
The increase of the glycerol waste concentration depressed CH 4 production and glycerol waste utilization.
On the contrary, this work demonstrated the addition of decanter cake as co-feedstock and microbial source, containing hydrolytic and acedogenic bacteria, yielded a better performance in the biogas production and simulate glycerol waste utilization at the same time. Publication date: Available online 11 January Source: International Journal of Hydrogen Energy Author s : David Ouellette, Edgar Matida, Cynthia Ann Cruickshank A single domain approach to resolving liquid saturation jumps and the water introduction rate within a flowing electrolyte - direct methanol fuel cell is presented.
The derivation demonstrates the importance of retaining the porous property dependency on the capillary pressure gradient to obtain a liquid saturation jump.
A proposed pulse function was shown to be a useful tool to approximating the macroscopic variations in porous properties across mating layers. The presented approach compared well against analytical solutions and experimental data. The overall performance of the fuel cell was shown to be rather insensitive to the choice of pulse diffusion index, suggesting that large scale simulations could reduce their computational cost with increased diffusion, without significantly affecting their predicted performance.
Leshchak, A. Syrotyuk, R. Barna The ambiguous relationship between fatigue crack growth rate and hydrogen concentration C H in the bulk of metal under cyclic loading of the ferrite-pearlite low-alloyed steel in hydrogen-contained environments has been found: there is a certain C H value at which the crack growth resistance of steel increases.
At these test conditions fracture surface demonstrates some increasing of the plastic component on relief. Torrell, A. Morata, M. Kendall, K. Kendall, A. Initial dual operation mode analyses revealed a strong influence of the carrier gas flow on the fuel cell degradation rate, showing a higher degradation rate when low fuel utilization FU conditions were employed under low total flow conditions.
These experiments evidenced that a suitable fuel-to-carrier gas ratio must be satisfied in order to avoid mass transport limitations. The structural and surface morphological studies of SnO 2 thin films were carried out.
The work envisions towards realization of targeted H 2 detection system at low temperature. In addition, the current ripple reduction using the proposed neural network MPPT controller allows to improve the efficiency of the fuel cell and extend its lifetime. Battista, Y.
Montenegro Camacho, S. Bensaid, A. Herrmann, H. Krause, D. Trimis, D. Fino BioRobur is a project aimed to produce hydrogen from biogas through an auto-thermal reforming ATR process, in which innovative catalytic systems are used to promote the ATR reactions involved in the process for the conversion of biogas into syngas.
LCA analysis has been also conducted for other two conventional processes for the production of hydrogen from biogas: the steam reforming and water hydrolysis a biogas-fueled Internal Combustion engine ICE followed by an Electrolyser. A comparison between these technologies has been made from both the environmental and the energetic viewpoints. Moreover, the ICE plus Electrolyser has resulted to be the because of the very large amount of biogas needed for the least efficient process, due to the low conversion yield of biogas into energy of the ICE.
Moharir In the present study, a comprehensive generic model is developed for pressure swing adsorption process. The model overcomes the inadequacy related to frozen solid concept, isothermality assumption etc. Hydrogen pressure swing adsorption process demands high purity and recovery, which can be achieved by complex cycle configuration. It has been used as a case study.
The present study reports separation of Hydrogen from five-component mixture using a six-bed process.
The dynamics of the process were studied and are presented incorporating non-isothermal effects. Although previous atomistic HE study is able to quantify hydrogen delivery to the crack tip with the stress intensity distribution, no mathematical model has been proposed to quantify the hydrogen effects in the complex loading spectra.