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101.
Günther Huber Otto Machhammer Maren Lepple Claudia Weidlich Cord-Henrich Dustmann Akane Hartenbach 《化学,工程师,技术》2021,93(4):664-672
A photovoltaic system could supply a single-family house with electrical power, warm water, and room heat if the energy would be distributed over the year to suit the load profile. However, storage systems for this are not state of the art yet. A concrete example is used to estimate which parameters such a power storage system should have. A suitable electrochemical reaction system based on inorganic salt mixtures is proposed. The German Federal Ministry of Education and Research is currently funding the development of a world storage facility based on the same reaction system. 相似文献
102.
To obtain the great surface quality of Ti–6Al–4V and achieve high efficiency in the polishing process, the chemistry enhanced shear thickening polishing (C-STP) was proposed, and the polishing performance of different pH slurry was studied. The results show that the material removal rate gradually increases as the pH value decreases from 10 to 1, and the best surface quality is obtained at pH 2. The corrosion current density and potential were measured by potentiodynamic polarization under three typical pH values. It is confirmed that the most massive corrosion rate presents at pH 2, and the passive film is most susceptible to be produced at pH 10. The reaction resistance was measured by electrochemical impedance spectroscopy to clarify the polishing mechanism. Under acidic conditions, the chemical reaction product on the surface can be quickly removed by mechanical action of the abrasive. On the contrary, the passive film formed on the surface under the alkaline condition is difficult to be removed. The corrosion reaction products were determined by X-ray photoelectron, and the chemical reaction under acid-base environment was derived. MRR reached 107.3 nm/min under the selected process parameters, and the surface roughness (Sa) is reduced from 124 nm to 8.6 nm within 15 min. 相似文献
103.
《International Journal of Hydrogen Energy》2020,45(53):28996-29008
Inventing an effective method to store large amounts of hydrogen at room temperature is one of the key challenges in developing a hydrogen-based economy. Metal hydrides have attracted attention owing to their promising hydrogen storage capabilities. We have systematically studied the structural and electronic properties of mechanically synthesized Ti0.5V1.5-xCrx (0 ≤ x ≤ 0.3) alloys and investigated the influence of the addition of Cr atoms on the hydrogen storage properties of vanadium-rich body-centered-cubic (V-BCC) alloys. X-ray diffraction (XRD) results indicate that all alloys are composed of BCC main phase, with the lattice parameters exhibiting no change following chemical modification. The kinetic measurements have revealed that Cr-containing alloys exhibit improved hydrogen uptake. X-ray photoelectron spectroscopy (XPS) measurements have shown that the addition of Cr has a significant effect on the anti-oxidation properties of V-BCC alloys, increasing their chemical activity and thus enhancing the hydrogen storage properties. Moreover, XPS results elucidate the role of activation of the studied materials. Additionally, the electrochemical properties of the negative electrodes (as part of Ni-MHx secondary batteries) made of Ti0.5V1.4-xNi0.1Crx (0 ≤ x ≤ 0.3) system have been studied by cyclic charge-discharge and demonstrate that doping of the V-BCC alloys with Cr can significantly improve the cycle-life stability of anode that exhibits similar discharge performance up to 50 cycles. First principles simulations are used to analyse the changes in the electronic density of states close to the Fermi level, as a function of Cr concentration, as well as binding energies and structural changes upon hydrogen absorption. Furthermore, ab initio studies confirmed that H absorption is favoured with increasing Cr-content. Our study highlights the importance of the addition of Cr to V-BCC alloys on both solid-gas and electrochemical hydrogenation reactions. 相似文献
104.
Muhammad Arsalan Noor-Ul-Ain Babar Ayesha Sadiqa Shakeela Mansha Nadeem Baig Laraib Nisar Muhammad Naeem Ashiq Tawfik A. Saleh Khurram Saleem Joya 《International Journal of Hydrogen Energy》2021,46(7):5207-5222
Nanoscale electrocatalytic materials having enhanced electroactive sites has been considered trendier and can drive kinetically uphill OER at much lower energy cost with high efficiency. However, very complex synthetic strategies, extensive functionalization processes, and less stability have stimulated quest for economically viable, straightforward and facile preparative methods for designing stable, robust and active nanoscale electrocatalysts engaging geologically abundant materials to ensure their industrial implications. Here we present surface-assembled Fe(OH)x/FeOx type colloidal catalytic thin-films, with or without post annealing, derived from Fe-colloidal NPs in simple carbonate system for efficient water oxidation. Comprehensive electrochemical studies including cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, Tafel slope analysis, mass activity, electrochemically active surface area measurements are conducted to comparatively evaluate the performance of simple (FeOx/HCO3?@FTO and annealed (FeOx/HCO3?@FTO250, FeOx/HCO3?@FTO500) catalysts for oxygen evolution reaction (OER) under employed conditions. The FeOx/HCO3?@FTO250 annealed at 250 °C initiates water oxidation at much lower overpotential of 1.52 V vs. RHE with remarkable stability during long-term electrochemical experimentations. In addition to enhanced OER activity as evidence by better onset potential (<1.55 V vs. RHE), lower Tafel slope value (36 mV dec1?) and negligible charge transfer resistance, the Fe(OH)x/HCO3?@FTO type catalyst presented excellent electroactive nature during long term controlled potential electrolysis experiments where more and more electroactive sites were getting exposed during continuous hours of electrolysis. The catalysts behave as a potential enduring, inexpensive and competent candidate for catalyzing water oxidation reaction when tested under begin conditions. 相似文献
105.
Grégory Odemer Eric Andrieu Christine Blanc 《International Journal of Hydrogen Energy》2018,43(2):1006-1011
Numerous studies have shown that Ni-based superalloy 718 may be sensitive to hydrogen embrittlement and have highlighted the dominant roles played by the hydrogen solubility and the hydrogen trapping. Samples were hydrogenated by cathodic polarization in molten salts under different conditions to vary the diffusible hydrogen content and to saturate the different hydrogen traps present in the microstructure strengthened by precipitation. Open circuit potential and galvanic coupling measurements were conducted in order to characterize the effect of diffusible and trapped hydrogen on electrochemical behavior and to discuss the possibility of galvanic coupling between zones with different hydrogen contents. 相似文献
106.
The repassivation behavior of Alloy 690 T T in simulated primary water at different temperatures was investigated by the rapid scratching electrode technique together with electrochemical measurements.The results showed that the repassivation process had three stages: the initial stage conformed to the place exchange model, the final stage conformed to the high field ion conduction model and in between there was a transition stage. At the initial stage, when the repassivation process of alloys was controlled by the place exchange model, anodic dissolution of substrate was dominated;after the film coverage rate was more than 0.99, the repassivation process of alloys was controlled by high field ion conduction model. Increasing the temperature resulted in a reduction of the repassivation rate and protectiveness of the passive film. The correlations among several mechanisms describing the repassivation behavior of alloys were discussed. 相似文献
107.
Jinlong Lv 《材料科学技术学报》2018,34(9):1685-1691
Mechanical property of coarse grained and nano/ultrafine grained alloy 690 and their corrosion resistance after immersion in high temperature borate buffer solution were investigated. The grain refinement significantly enhances the tensile strength of the alloy 690. In addition, the grain refinement facilitates the formation of the deformation twin which improves the ductility of the alloy 690. It has been found that the grain refinement promotes to form more Cr2O3 on the surface of the alloy 690 in high temperature borate buffer solution. At the same time, the grain refinement inhibits the formation of spinel type oxides. More hematite type oxides formed on nano/ultrafine grained alloy 690 improves its corrosion resistance in borate buffer solution. The hematite type oxides have a lower concentration of point defect than that of the spinel type oxides, which results in an excellent corrosion resistance of nano/ultrafine grained alloy 690. These results are supported by the Mott-Schottky analysis and the point defect model. 相似文献
108.
《Advanced Powder Technology》2022,33(8):103670
Tin is one of the vital substances in the material and chemical industry. Deep eutectic solvent (DES) possesses excellent physicochemical properties for metal preparation. In this study, the electrochemical behavior of Sn(II) and metallic tin preparation in choline chloride-ethylene glycol (ChCl-EG) DES were investigated. Linear sweep voltammetry is carried out to study the effects of substrate material (Ni, Cu, Pt, C, Fe, Al, W, glassy carbon (GC) and Ti), temperature (313–353 K) and SnCl2 concentration (10–100 mM) on the electrochemical behavior of Sn(II)/Sn. Results demonstrate that metallic tin is easier to be prepared on the Ni electrode, and increasing temperature and SnCl2 concentration both facilitate the reduction of Sn(II). Electrospray ionization mass spectrometry (ESI-MS) shows that the main form of Sn(II) is [SnCl3]-. Chronoamperometric tests indicate that with the increase of applied potential, the nucleation of Sn(II) on the nickel electrode becomes close to the instantaneous nucleation. Simultaneously, the nucleation rate and the number of active sites on the electrode surface increase significantly. Pure tin with a dendritic structure could be prepared with higher current efficiency of 96.4% and lower energy consumption of 320.5 kW·h·t?1 without any additives. All these studies provide a fundamental basis for the preparation of tin powders in ChCl-EG DES. 相似文献
109.
Si/Graphene nanoparticles represent attractive alternative anode materials for Lithium-ion batteries. Graphene nanosheets with different properties, including surface area, defect distance, and charge-transfer resistance, were fabricated and characterised in Si/Graphene nanocomposites formed by static-electric self-assembly then by an in-situ reduction process. Graphene nanosheets that exhibited the highest surface area, the shortest defect distance, and the lowest charge-transfer resistance demonstrated the best overall electrochemical performance, with a high initial discharge capacity of 2692?mAh?g?1, good cycling performance of 1135?mAh?g?1, at the 200th cycle at the current rate of 0.5?C. This work shows the preferable graphene quality for Si/Graphene nanocomposite anode and provides insights into the design of graphene nanocomposite electrodes, regardless of the graphene synthesis method. 相似文献
110.
J. C. Forti J. A. Nunes M. R. V. Lanza R. Bertazzoli 《Journal of Applied Electrochemistry》2007,37(4):527-532
The performance of a catalyzed H2O2 electrogeneration process using a modified oxygen-fed graphite/PTFE electrode is reported. The organic redox catalyst chosen
for incorporation into the graphitic mass was azobenzene. The yield of the hydrogen peroxide is related to the applied potential
and to azobenzene concentration. Modification of the gas diffusion electrode with azobenzene improved hydrogen peroxide production,
and the overpotential for oxygen reduction was shifted to less negative values compared to the performance of a non-catalyzed
electrode, indicating that these modified electrodes have good electro-activity. 相似文献