查看更多>>摘要：? 2022 Elsevier B.V.Due to the low recrystallization temperature, the microstructure of wrought Zn alloys is naturally unstable, which affects their mechanical properties and limits their application. Therefore, it is crucial to elucidate the effect of microstructural evolution on mechanical properties of wrought Zn alloys. In this work, annealing treatment was performed on a Zn-0.5Cu (wt%) equal channel angular pressure (ECAP) alloy at 200 °C for different durations to investigate the microstructure evolution and its effect on the mechanical properties. An abnormal phenomenon that strength and ductility of the ECAP alloy decrease monotonically with increasing annealing time was observed, which is remarkably different from most other metallic alloys (Mg, Al, Cu, etc.). Detailed microstructure observations were conducted to unveil the mechanisms behind this abnormal phenomenon. Annealing for 1440 min induced not only an abnormal increase in texture intensity from 17.06 to 30.53 (which can be ascribed to preferential growth of high-texture grains with the<?12 to 10 >and<01–10 >components) but also a significant grain growth from 3.3 μm to 32.7 μm. Grain growth and dislocation annihilation resulted in the loss of strength, while the abnormal decrease in ductility during annealing was primarily due to texture enhancement and grain coarsening. The present work could provide guidance for the production and application of wrought Zn alloys in biomedical fields.
查看更多>>摘要：? 2022 Elsevier B.V.The development of flexible memory devices has been attracting more and more interests to advance next-generation lightweight and wearable electronics. Though HfO2-based ferroelectric thin film has shown promising future for the mass-production of low-cost ferroelectric memory, the fabrication of HfO2-based ferroelectric devices on thermosensitive flexible substrates has been a practical challenge due to the necessity of a high temperature thermal process to reach its potential of ferroelectric high-performance. In this work, a flexible Pt/W/Hf0.5Zr0.5O2/W/Pt multilayer stack with excellent ferroelectric properties is fabricated on PET by a controlled spalling technology, which is simple, reliable and cost-efficient. AFM characterizations proved that multilayer film exhibited a smooth surface after spalling process, and the e-testing results showed that Hf0.5Zr0.5O2 film did not show obvious deterioration in ferroelectric properties during spalling and transfer. Furthermore, the flexible Hf0.5Zr0.5O2 ferroelectric films maintained superior polarization, retention, and endurance performance under a series of bending deformations and cycling tests, indicating its outstanding mechanical resilience. This work is of great significance for the practical application of new HfO2-based thin film flexible ferroelectric memory in wearable electronics.
查看更多>>摘要：? 2022 Elsevier B.V.Limit caused by insufficient charge transfer between interfaces is one of the current topics in the photocatalytic degradation of pharmaceuticals and personal care products (PPCPs). Photocatalysts designed as 2D/2D/2D structures have a faster separation rate of the heterojunction interface and a better carrier transfer speed to improve their performance. In this work, 2D CuO nanosheets have been synthesized by the drip method at normal temperature. And layered MXenes are introduced as the charge transfer bridges into the system of O-doped g-C3N4 nanosheets and CuO nanosheets to construct a 2D/2D/2D CuO-MXene-OCN S-scheme heterojunction. The photocatalytic performance of CuO-MXene-OCN is much higher than CuO-OCN heterojunction due to the intimate interaction between interfaces. The degradation efficiencies of different PPCPs in 60 min under visible light irradiation are 98.2 % for TC, 75.6 % for MT, 92.6 % for DCF. This unique interfacial engineering gives new insight into the construction of layered S-scheme heterojunctions with 2D/2D/2D structure for photocatalytic degradation of PPCPs.
查看更多>>摘要：? 2022 Elsevier B.V.We report synthesis and characterization of Co3O4-decorated porous TiO2 nanofibers obtained through a facile electrospinning followed by a hydrothermal process. A morphological characterization confirmed that the diameter of the nanofiber was 250–300 nm. It was composed of subgrains, while its surface was decorated with Co3O4 nanoparticles with a diameter of 30–50 nm. The nanofiber had a porous body structure, which was conducive to the adsorption of acetone gas. The synthesized Co3O4-decorated porous TiO2 nanofibers were used as sensing materials to fabricate acetone gas sensors. Their response and recovery times were systematically analyzed with respect to the operation temperature and acetone gas concentration. The observed gas response, response time, and recovery time of the nanofiber-based gas sensor were 71.88, 122 s, and 351 s, respectively, for 100-ppm acetone gas at an optimized temperature of 250 °C. Therefore, the Co3O4-decorated porous TiO2 nanofibers could be a promising candidate for the fabrication of high-selectivity acetone gas sensors.
查看更多>>摘要：? 2022 Elsevier B.V.Exploring highly active and cost-effective metal-based overall water splitting catalysts are crucial for the large-scale conversion of sustainable electrical energy to fuels, feedstocks and green economy. Here, a nickel foam-supported electrocatalyst consisting of a one-dimensional Co3O4 nanowire and two-dimensional NiFe-LDH nanosheets is reported. The optimized Co3O4@NiFe-LDH/NF catalyst affords 79 and 215 mV at 10 mA cm?2 for catalyzing the hydrogen and oxygen evolution reaction in 1.0 M KOH, which also exhibits quick reaction kinetics and excellent durability. The self-supported electrode only requires 1.58 V to afford 10 mA cm?2 with astonishing stability for water splitting. The linked interfacial nanostructure between NiFe-LDH and Co3O4, which supports the enhancement of the electronic structure and increases catalytic active sites, is primarily responsible for the electrode's remarkable catalysis performance. The Co3O4@NiFe-LDH/NF as an ideal electrocatalyst lays forth a broad technique for synthesizing electrocatalytic materials for efficient and scalable water splitting.
查看更多>>摘要：? 2022 Elsevier B.V.Wood is a main component of the forest ecosystem and also a versatile raw material with enormous potential for application. Its application ranges from construction material to an important source of energy. A balanced stand of hardwoods and conifers can be assumed in the future due to the increased establishment of mixed forests. The usage of wood as an environmentally friendly material combines an optimised room aesthetics with mechanical and/or acoustic functionality. Instrument makers have long been aware of the special acoustic properties of wood. This awareness is moving into the interest of transportation. It has an increasing social acceptance. Ultimately, wood is experiencing a renaissance. Cellular materials like wood play an important role in applications where vibration amplitudes and noise need to be reduced. In general, wood is considered to have low damping properties due to its molecular structure and its relatively high modulus of elasticity. Nevertheless, further studies into its acoustic properties are essential in order to be established as an alternative substitute material. In this work, plates made of spruce, maple and cherry wood were mechanically excited in the centre on the back. The acoustic intensity of the panel on the other side was then measured as a spatial function using an acoustic sensor. On the one hand, the results showed a different vibration pattern between the softwood spruce and the hardwoods maple and cherry. On the other hand, the intensity of the acoustic radiation was different. These results were discussed on basis of the structure-dependent damping of wood.
查看更多>>摘要：? 2022 Elsevier B.V.Highly luminescent GdVO4:Eu3+/carbon dots (CDs) nanocomposite was synthesized by hydrothermal deposition method for the first time. With the use of dialyzed CDs solution as precursor, the synthetized composite shows negligible emission intensity of CDs. On replacing the dialyzed CDs solution with the crude one, highly luminescent composite can be obtained successfully. Based on the analysis of XPS and FT-IR spectra, one can deduce that the existence of a large amount of citrate anions, ethylenediamine cations and polymer-like CDs in the crude CDs solution make it as nutrient solution of CDs, which can not only facilitate growth of CDs on the surface of GVE, but also greatly prevent nitrogen atoms from falling off the particles during the hydrothermal deposition process. For the dialyzed CDs solution, due to the ions and polymer-like CDs being thoroughly dialyzed, the coated CDs are fragile during hydrothermal deposition process. Besides, the effects of different dosages of ammonia on emission intensities of the two composites are studied. Based on the designable patterns for security application, one can think that the highly luminescent composite is one of the most promising candidates in the anti-counterfeiting field.
查看更多>>摘要：? 2022 Elsevier B.V.A two-step thermal condensation approach was developed to fabricate Cu and graphic carbon nitride (g-C3N4) composites. Cu nanocrystals (NCs) with a size range of 2 – 5 nm were embedded in superior thin g-C3N4 nanosheets. Although little amount of Cu NCs was incorporated in g-C3N4 nanosheets, Cu/g-C3N4 composites revealed promoting influence towards photocatalytic H2 generation and photodegradation of pollutions. Namely, the sample 680-Cu0.05% (with Cu of 0.05 wt%) revealed the best photocatalytic performance. Electrochemical test indicates that Cu NCs improve the productivity of the samples. Narrowed band gap in Cu/g-C3N4 composite samples resulted in an expanded photo adsorption in visible light range. The composites also revealed enhanced optical current response and small interfacial charge transport resistances compared with pure g-C3N4 nanosheets (sample Pure-680). The photocatalytic H2 generation rate of the composite was ~ 2790 μmol g?1 h?1, which is 2.3 times of that of Pure-680. The degradation efficiency of rhodamine B using the composite sample reached 95.5 % with a photodegradation rate of 0.0774 min?1 and was described a zero-order kinetics model (C0-C=kt) with a process completing within 35 min. The test of photocatalytic hydrogen evolution stability indicated that it was almost no degradation when using the composite sample after 8 cycles. This work proposes an efficient method to improve the separation and transfer efficiencies of photogenerated carriers in g-C3N4 and could be applied in another two-dimensional composite photocatalysts.
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