查看更多>>摘要：? 2022 Elsevier B.V.Designing of two dimensional surfaces and interfaces with light-active materials has been established as a versatile approach to increase their photocatalytic activity. In the present work, n-type anatase TiO2 coupled with p-type B-doped g-C3N4 nanosheet (BCN) were fabricated and Au-Cu nanoalloy with varying atomic ratio were deposited on the p-n heterojunction. The incorporation of Au-Cu on the interface of the dyad enhances light absorption over broad regime, charge separation, and migration. Au-Cu with 1:1 ratio (with an average particle size of 1.2 nm) loaded p-n hetrojunction (TBCAC-1:1) shows excellent photocurrent enhancement (approximately 4.4-folds) in the cathodic direction as compared to their monometallic plasmonic counterpart. Additionally, the catalyst shows photocurrent at zero biased potential as well as lower onset potential as compared to the other alloy. TBCAC-1:1 photocatalyst could able to produce 2150 μmol h?1g?1 of hydrogen, which is (approximately 3-folds) as compared to their monometallic counterparts. The hydrogen evolution process for Au-Cu (1:1) system was found to be governed by the charge distribution which dictates the binding preference of the Au and Cu sites leading to the water splitting as investigated by DFT calculation. The excellent hydrogen generation by the photocatalyst links to the synergistic effect between Au and Cu associated with the hot electron photochemistry due to surface plasmon resonance phenomenon.
查看更多>>摘要：? 2022 Elsevier B.V.A novel layered double hydroxide (LDH)/silane bilayer system was introduced as an effective non-hazardous protective coating for AA2024-T3. Also, the loaded corrosion inhibitors' effect on the bilayer coating system's active anticorrosion properties was studied. For this purpose, diethyldithiocarbamate (DEDTC) molecules, as an eco-friendly corrosion inhibitor, were intercalated in the LDH conversion layer. Furthermore, Ce3+ cations were loaded in the sodium montmorillonite and then incorporated in the mixture of tetraethoxysilane and γ-amino propyltriethoxysilane. The grazing incidence X-ray diffraction, Fourier-transform infrared spectroscope, and scanning electron microscope (SEM) equipped with energy dispersive spectroscope were used to analyze the structural, surface functional groups, microstructure, and chemical composition of the coatings. Electrochemical impedance spectroscopy, potentiodynamic polarization, and electrochemical current noise technique were employed to investigate the layers' protection behavior. Based on the obtained results, the presence of corrosion inhibitors in the structure of the coatings resulted in a dramatic enhancement in the protection behavior of the substrate. The polarization results illustrated that the corrosion current density of the bilayer system was reduced from 170 to 6.7 nA/cm2 after employing the corrosion inhibitors into the coating structure. The electrochemical tests and SEM results illustrated the induction of the active anticorrosion properties for the bilayer system containing the DEDTC molecules and Ce3+ cations. The total noise energy for the scratched double-layer coating in the presence and absence of corrosion inhibitors was calculated to be 4.1 and 9.5 pA2, respectively, indicating efficient corrosion inhibition.
查看更多>>摘要：? 2022 Elsevier B.V.By using in-situ synchrotron angle-dispersive X-ray diffraction measurements, the thermal expansion and compressibility of orthorhombic CaSc2O4 were investigated up to 1173 K at ambient pressure and up to 15.9 GPa at room temperature, respectively. No phase transformation was observed in this study. The thermal expansion coefficients of CaSc2O4 were determined to be 4.17(3) × 10?5 K?1, 1.60(1) × 10?5 K?1, 1.18(1) × 10?5 K?1 and 1.39(1) × 10?5 K?1 for the V, a-, b- and c-axis, respectively. The isothermal bulk modulus of CaSc2O4 was obtained as 153.8(50) GPa with its first pressure derivative of 6.5(9). The axial compressibility was estimated to be 123(3), 177(4) and 242(11) GPa for the a-, b- and c-axis, respectively. Both the thermal expansion and compressibility of CaSc2O4 show axial anisotropy. The heat capacities (Cv and Cp) of CaSc2O4 was estimated by using a Kieffer model with Raman spectroscopy data and present experimental results. The standard entropy (S2980) and Debye temperature (θD) of CaSc2O4 were also calculated.
查看更多>>摘要：? 2022 Elsevier B.V.It is still enormously challenging to design carbon-based electrode materials with good performance under a high mass loading to satisfy the demand for lightweight supercapacitors in applications. Herein, interconnected hierarchical porous carbon materials with an appropriate content of heteroatoms (O, S, and N) are synthesized using a green radish precursor. The prepared porous carbon is approximately spherical with a size range of 35–95 nm and a microporous-mesoporous structure. The corresponding specific surface area and total pore volume are 2415 m2/g and 1.386 cm3/g, respectively. The electrochemical behavior, capacitance sources, and reaction kinetics mechanisms of the prepared material were carefully studied. As a result of its structural properties, the porous carbon in a three-electrode system with a 6 M KOH electrolyte exhibited a high areal capacitance of 3.55 F/cm2 at 0.5 A/g and 2.97 F/ cm2 at 20 A/g under a high mass loading of 10 mg/cm2. In a coin cell, the capacitance and the energy density of the porous carbon reached 258 F/g (at 1 A/g) and 9.2 Wh/kg (at a power density of 247.5 W/kg), respectively. The hierarchical pore distribution and heteroatom-enriched structure of the porous carbon result in a large ion-accessible surface, fast charge/mass diffusion channels, and excellent wettability. Thus, the porous carbon exhibits high specific capacitance, good rate performance, and superior energy density at a high mass loading.
查看更多>>摘要：? 2022 Elsevier B.V.Improving the performance of anode materials is of great importance for lithium-ion batteries (LIBs). Transition metal selenides compositing carbon and germanium (Ge) have attracted extensive attention. In this work, an anode material that integrates Ge and α-MnSe in carbon nanofibers (CNFs) was first synthesized by heat treatment after electrospinning. The coupling of Ge with α-MnSe and carbon can cause the growth process of α-MnSe to occur inside the CNFs, which can buffer the volume change, refine the grains and avoid particles protruding from the surface of CNFs. In addition, the interconnected conductive network of Ge/α-MnSe@CNFs can provide fast diffusion channels for Li ions and improve the electrical conductivity. Importantly, there is a synergistic effect of Ge, α-MnSe, and CNFs on the anode material for LIBs. As expected, Ge/α-MnSe@CNFs exhibited an excellent performance with a capacity of 1514.7 mAh g?1 after 200 cycles at 0.1 A g?1 and 1030 mAh g?1 after 1000 cycles even at 1 A g?1. Therefore, this new preparation strategy of Ge/α-MnSe@CNFs offers novel ideas to develop high-performance and long-life LIBs.
查看更多>>摘要：? 2022Powder metallurgy Cu-30Fe alloy was prepared by mechanical alloying, pressureless sintering, and rolling processes. The alloy microstructure and physical properties affected by rolling were studied. The Fe particles were small and uniformly distributed in the Cu matrix. The average Fe particle size in the sintered state was 1 μm, and particles had subspherical or irregular shapes. The Fe particles became elongated, tadpole-shaped, and spindle-shaped as a result of rolling. At the same time, the Cu grains were elongated and refined, while the Cu grains near the Fe particles were finer as a result of the coordinated deformation of the soft Cu and hard Fe phases. After annealing at 400 °C, the cold-rolled Cu-30Fe alloy had 620 MPa tensile strength, 10% elongation, and 50% IACS electrical conductivity, achieving a good combination of mechanical and functional properties. The coordinated deformation behavior and grain refinement mechanisms of both Cu and Fe phases due to rolling were described, along with the microstructure and physical properties evolution.
查看更多>>摘要：? 2022Metal-ceramic joints represent an important choice for biomedical devices, in orthopaedic field or as micro-stimulators. ZrO2-Ag-HEA joint is here proposed to replace the currently used Ti6Al4V by new Ti-based refractory HEAs. To evaluate the system reactivity, wettability of ZrO2 by different Ag-based alloys at 1000 °C and their interfacial layers were studied, for the first time. Interpretation and discussion of systems reactivity were supported by thermodynamic calculations, according to the CALPHAD approach and the ad-hoc Ag-Ti-Zr-O thermodynamic database, implemented in this work. A good wettability was reached at 1000 °C adding Ti to Ag: Ag-4Ti and Ag-8Ti reached contact angles of 81–85°. Ag-4Ti-2Zr showed the best wettability (77°) and the most complex interfacial microstructure. A continuous hcp (Ti,O), ~ 20 μm thick, promoted the wettability of Ag-4Ti and Ag-8Ti. In both cases, AgTi was the only intermetallic compound found in the bulk. Ag-4Ti-2Zr formed a thicker interfacial layer of hcp-(Ti,Zr,O) + bcc-(Ti,Zr) + a less compact Ag(Ti,Zr)2 layer. Here, a low amount of Ag(Ti,Zr) and Ag(Ti,Zr)2 was found in the Ag matrix. Since Ag resulted a promising filler to braze Ti-rich substrates to ZrO2 at 1000 °C, preliminary HEA-Ag-ZrO2 joints were characterized. A sound and defects-free interface was observed, with a first layer, mainly formed by Ag, Ti and Zr (HV ~ 600), and a Ag-based interface (HV ~ 250), extending until the HEA. Further works envisage mechanical and electrochemical evaluations of the system to pave the way for the production of novel HEA-Ag-ZrO2 joints to be used in biomedical applications.
查看更多>>摘要：? 2022 Elsevier B.V.The synchrotron radiation X-ray absorption fine structure (XAFS) technique is used to study the local structure of the key atom Ru in a series of Ni-Al-Ru ternary alloys with different Ru contents and heat treatments. All the investigated alloys consist of two phases, γ and γ', and especially Ru exists as an atom coordinated by 12 Ni atoms in the first shell without Ru clusters or intermetallic compounds. In γ phase Ru resides on the Ni lattice site introducing an outward relaxation of the neighboring atoms, while in the γ' phase Ru replaces the Al lattice site causing an inward relaxation. The interatomic distance of Ru–Ni bond and Debye-Waller factor are mainly affected by the composition and increase with the increasing Ru content. While the effect of heat treatment is obvious when the Ru content is higher than 6 at%. The variation of Ru local atomic structure can greatly influence the microstructural evaluation and deformation mechanism by changing the lattice misfit and the vacancy formation energy to control the creep properties of Ni-Ru-Al ternary alloys.
查看更多>>摘要：? 2022 Elsevier B.V.Energy depletion has led to the demand for new versatile materials with energy transmission and storage properties. Therefore, in this study, adhesive-free film structure of the NiSb alloy materials was obtained in one step through a simple and economic microwave synthesis technology using nickel foam as the source of nickel. X-ray analysis confirmed the successful preparation of NiSb nano-structures. In addition, electrochemical studies indicated that the adhesive-free film structure has a high capacity (4633 F g?1) and good cycle stability, and the capacitance value of this material was higher than that of previously reported alloy electrode materials such as MnCo and NiSn. In addition, we assembled an asymmetric supercapacitor with NiSb and activated carbon as the positive and negative electrode, respectively. The solid-state asymmetric supercapacitor had a working voltage of 1.7 V, and it exhibited a maximum energy density of 481.7 μWh cm?2 at 1630 μW cm?2, indicating the good energy transmission and storage properties of the NiSb nanomaterials.
查看更多>>摘要：? 2022 Elsevier B.V.RuO2 nanorod-decorated tubular carbon nanofibers(CNFs) are carefully fabricated by adjusting the recrystallization temperature for use in high-performance electrochemical capacitors. The tubular structured CNFs/RuO2 electrodes provide a short diffusion path for the ion transport through the inner hollow channel that allowed the maximum utilization of the active sites of the amorphous RuO2 nanomaterials at the electrode/electrolyte interface. The optimized the tubular structured CNFs/RuO2 electrodes exhibit good rate capability with a high surface capacitance, energy density, and good long-term cycling stability of 190 Fg?1, 22 Whkg?1, and 94% after 10,000 cycles, respectively, in an aqueous solution. The asymmetric cell presents a wide and stable operating voltage window, which greatly improves the energy density stored in the asymmetric device. In addition, there is no noticeable difference in the electrochemical properties under bent states, making it a flexible energy storage device for wearable applications. Hence, flexible supercapacitors using CNFs/RuO2 electrodes with the tubular structure show low resistance, high capacitance, good rate retention, and excellent cycle stability, making it a promising material for energy storage applications.
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