查看更多>>摘要：? 2022 Elsevier B.V.One of the most promising approaches in wastewater treatment technology to purify water from cyclic organic compounds and bacteria simultaneously is to use semiconductor nanoparticle based photocatalysts. Ni-doped SnO2 nanoparticles were obtained via co-precipitation method, synthesis procedure was developed to obtain nanoparticles with the same size and shape, but different concentrations of dopant ions and various amounts of defects. It was established that amount of defects, including oxygen vacancies, can be regulated via variation of the synthetic procedure. Obtained nanoparticle samples were tested as photocatalysts on a methylene blue solution under different light sources, including cheap widely available LED lightbulbs. More than 80% of methylene blue degradation was achieved within 60 min. The key parameter affecting the nanoparticles photocatalytic activity, namely the vacancies and defects amounts ratio, was revealed for the first time for three types of photocatalytic procedure (various light sources and stirring methods). Antibacterial activity against E.coli bacteria was studied under bubble stirring, the inhibition activity close to 60% after two hours of irradiation was shown and can be predicted by taking into account the oxygen vacancies and defects amounts ratio and the interaction energy of oxygen molecule with nanoparticle surface. The way for the rational design of simple in production photocatalyst for wastewater treatment was formulated based on experimental and computational data.
查看更多>>摘要：? 2022 Elsevier B.V.Vanadium-based materials are largely studied as electrochemical energy storage materials. Herein, the dual-monoclinic δ-NaxV2O5/VO2(B) composite is synthesized by a simple hydrothermal method. Because of the synergistic effects of monoclinic NaxV2O5 and monoclinic VO2(B), the composite presents good electrochemical performance, including a high capacity of 399 mAh g?1 at 0.2 A g?1 and an excellent rate performance of specific capacity of 267 mAh g?1 at 4 A g?1. Combining monoclinic NaxV2O5 and VO2(B) can obtain special synergistic effects confirmed by crystal structure analysis and electrochemical characterization that the capacitance contribution of NaxV2O5/VO2(B) composite can reach 86.9 % at a scan rate of 1.2 mV s?1. This work designs and synthesizes a new composite cathode material with enhanced synergistic effects, promoting the application of vanadium-based material in aqueous zinc ion batteries.
查看更多>>摘要：? 2022 Elsevier B.V.We demonstrated a method via applying a lateral pre-strain to achieve a positive stretching dependence of resonance frequency in CoFeB films. An artificial wrinkling surface structure by adhering CoFeB films to biaxially pre-strained elastomeric polydimethylsiloxane (PDMS) supports was employed to fabricate stretchable magnetic films. The lateral growth pre-strain was used to adjust the longitudinal stretching dependence of resonance frequency of CoFeB films. For the sample fabricated on an elastomeric support that can freely contract in the lateral direction, the resonance frequency fr monotonously decreases with applying a tensile strain εapp. For the sample fabricated on an elastomeric support that can partially contract in the lateral direction, the fr first decreases and then increases as the εapp increases. The sample fabricated on an elastomeric support in which the lateral contraction is strictly limited display a positive stretching dependence of fr in the whole range of εapp. Thousands of fatigue tests show that the stretching dependence of microwave properties have a good repeatability.
查看更多>>摘要：? 2022 Elsevier B.V.We have investigated the magnetic properties and micromagnetic structure of multilayer Co/Pt films with the variation of bilayer thickness ([Co(0.3 × t nm)/Pt(0.5 × t nm)]10). The films represent Co-Pt alloys with periodic Co vs Pt composition. The magnetic force microscopy and Lorentz transmission electron microscopy have demonstrated the presence of N é el-type skyrmions in the films. The density of skyrmions was found to be strongly dependent on the bilayer thickness parameter (t). The effect is attributed to Dzyaloshinskii–Moriya interaction which is known to be strongly dependent on the regularities of magnetic and nonmagnetic layers alternation. We emphasize that the investigated system represents an intermediate case between unalloyed multilayer films and uniformly mixed alloys. Despite that it demonstrates similar micromagnetic behavior with skyrmion density very well controllable by modulation of technological parameters.
查看更多>>摘要：? 2022 Elsevier B.V.Microwave dielectric ceramics with excellent properties and low sintering temperatures are pursued saving energy and cofiring with metal electrodes (especially Ag, Cu). Herein, a low-firing Na2CaTi2Ge3O12 garnet was fabricated via a simple solid-state method. XRD, SEM, Raman spectrum, and dielectric characterization were used to reveal the influence of sintering temperature on crystal structure and dielectric properties. A single-phase Na2CaTi2Ge3O12 ceramic densified at 960 °C has the optimized dielectric properties with εr = 15.3 ± 0.2, Q×f = 55,900 ± 2000 GHz, and τf = ?15.7 ± 0.5 ppm/°C. The infrared (IR) spectrum was applied to estimate the intrinsic contribution of lattice vibration to microwave dielectric properties. The anti-reductive feature of Na2CaTi2Ge3O12 ceramic was evaluated via sintering at a reducing atmosphere while cofiring with Cu electrodes. The good chemical compatibility with Ag and Cu electrodes manifests the potential prospect of Na2CaTi2Ge3O12 ceramic in the low-temperature co-fired ceramic (LTCC) application.
查看更多>>摘要：? 2022 Elsevier B.V.Photocatalytic redox technology is established in energy and environmental governance with its environmentally friendly and broad-based optical source. However, the development of photocatalysts with strong redox ability still remains urgently desirable. Herein, an oxygen vacancy-engineered 2D/2D Z-scheme heterojunction photocatalytic materials of MoO3/g-C3N4 are synthesized, which achieves a trade-off between the value band position of MoO3 with high oxidation property and the conduction band position of g-C3N4 with high reduction property. The 2D/2D heterojunction manifests excellent functionality for photocatalytic H2 evolution and tetracycline degradation. Particularly, 3 % MoO3/g-C3N4 provides the optimum H2 generation rate (328.75 μmol g?1 h?1) without any noble metal cocatalyst, which is about 87-fold higher than that of pure g-C3N4 (3.78 μmol g?1 h?1). Moreover, the TC degradation kinetic constant of 3 % MoO3/g-C3N4 (0.0196 min?1) is about 8.28 times of pure g-C3N4 (0.0023 min?1). The outstanding photo-catalytic ability mainly comes from the interfacial interaction between 2D MoO3 and 2D g-C3N4, which can shorten the transport distance of charge carriers and contribute abundant active sites to improve the separation efficiency of photogenerated carriers. Furthermore, the oxygen vacancies (OVs) strengthen the redox potential of the system and serve as effective trapping sites for photogenerated carriers to reduce the quenching rate of photogenerated electrons. This work provides a feasible strategy to develop 2D/2D Z-scheme photocatalytic systems with high photocatalytic performance on energy storage and environmental application.
查看更多>>摘要：? 2022 Elsevier B.V.Vanadium oxides have a wide range of applications in aqueous zinc ion batteries due to their abundant resources and multiple valence states. However, the inherent low conductivity and structural instability of Vanadium-based materials often lead to the rapid degradation of their capacity. Consequently, stable microstructure and coordinated ion transport channels are essential to improve electrochemical performance. In this work, we report a surfactant-assisted hydrothermal method to obtain NaV6O15 with rod-like morphology and good dispersion. The surfactant-assisted NaV6O15 (NVO-I) electrode exhibited better cycle stability than the electrode without surfactant (NVO-II) during long cycles. The ordered morphology facilitated contact between the electrode and electrolyte, so the NVO-I electrode showed high electrochemical performance. The reversible capacity was 290.2 mAh g?1 at 0.1 A g?1, and the capacity retention was 95 % after 900 cycles at 1.0 A g?1. The surfactant-assisted hydrothermal strategy provides more options for developing stable and efficient AZIBs than other techniques.
查看更多>>摘要：? 2022 Elsevier B.V.It is significant to fabricate cheap and active compounds used in energy conversion. Herein, a new nano-micro composite was facilely fabricated by constructing two-dimensional Cu carboxyphenyl porphyrin metal-organic framework (CTMOF) on TiO2 microspheres (TMS). It showed that the light absorption and the transfer of photogenerated charges in TMS could be greatly improved by the introduction of CTMOF. Importantly, the obtained nano-micro composite (TMS/CTMOF) displayed excellent performance in photocatalytic hydrogen production. Under the same condition, its photocatalytic hydrogen evolution (86.11 mmol g?1, 6 h irradiation) was 14.5 times and 21.2 times of pure TMS and CTMOF, respectively, indicating the synergetic effect of TMS and CTMOF. Moreover, after 5 cycles (Every cycle was 6 h), the photocatalytic stability of the nano-micro composite was still greatly higher than those of the pure TMS and CTMOF. Furthermore, photocatalytic mechanism was clarified in order to demonstrate the improved activity in the nano-micro composite. This research will provide new ideas for constructing greatly active composite systems for photocatalytic H2 evolution.
查看更多>>摘要：? 2022 Elsevier B.V.A Zn-P bond oriented black phosphorus/CuInZnS S-scheme heterojunction was successfully constructed for tetracycline (TC) degradation and synergistic H2 generation. An enhanced photocatalytic H2 revolution rate of 2056.0 μmol/h/g was achieved with triethanolamine (TEOA) as the hole sacrifice agent, which was nearly two times higher than that of CuInZnS (CIZS) and 170 times that of black phosphorus (BP). To further improve the hole utilization rate and reduce the energy consumption, an appropriate amount of TC was added instead of TEOA, and an improved photocatalytic H2 generation rate of 1921.2 μmol/g was obtained with the synergistic degradation of TC by 82%. The types of heterojunctions and the transfer process of carriers were investigated by the combination of Mott-Schottky curves, Ultraviolet photoelectron spectroscopy, UV–vis diffuser reflectance spectra, and density functional theory. The results showed that a S-scheme heterojunction is built in BP/CIZS, which maintained the high redox ability of electron-hole pairs based on the successful separation of carriers. In addition, the novel Zn-P bond provided a charge transport channel and catalytic reaction active center upon photocatalysis. The design and application of photocatalysts proposed in this work offered a new idea for the coordinated resolution of environmental purification and energy conversion problems.
查看更多>>摘要：? 2022 Elsevier B.V.W-based composites with the different immiscible second phases (Cu and Cu10Sn) were prepared by laser powder bed fusion (LPBF). The immiscible W phase and Cu/α-Cu phases were prone to separate during LPBF. The melted W phase could easily fuse together and form W matrix, and Cu or α-Cu phase distributed within the gaps among W phase. Cu or α-Cu phase can provide a gradient cooling way for the solidification of W phase through the transformation of ‘solid-liquid-gas’ during LPBF. The evaporation of Cu or Sn accelerated the heat dissipation, which caused the grain refinement of W. Higher thermal conductivity of Cu than α-Cu leads to the relative finer grain size of W phase in W-Cu composite. The heat conduction direction between W phase and Cu/α-Cu also affected the grain morphology. Heat continued transferred from W to Cu/α-Cu induced the columnar grain growth of W, the interlacing distribution of W and Cu/α-Cu made the growth of W columnar grains radiate out from the center Cu/α-Cu phase. Remarkable, cracks were severely restrained in W phase simultaneously although W phase melted completely. This is not only related to improvement of strength and ductility of W caused by grain refinement, but also because of the interlacing distribution of W and Cu/α-Cu phases, which could effectively reduce the stress degree in W phase during LBPF.
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