今日更新:Composites Part B: Engineering 2 篇
Enhanced photocatalytic performance of MXene-Modified cation-exchanged CoFe-LDH/CoFeCrO4 heterostructure for Antibiotic degradation and hydrogen production through synergistic charge dynamics
Lekha Paramanik, Lagnamayee Mohapatra, Dong Yun Choi, Seung Hwa Yoo
doi:10.1016/j.compositesb.2024.111416
通过协同电荷动力学提高 MXene 改性阳离子交换 CoFe-LDH/CoFeCrO4 异质结构在抗生素降解和制氢中的光催化性能
Systemizing an effective charge-transfer channel across a junction interface replete with ample active sites for enhancing the photocatalytic activity of semiconducting materials presents a formidable challenge. Here, we present a novel approach based on an in situ hydrothermal method for synthesizing CoFe-Layered Double Hydroxide (LDH)/CoFeCrO4 heterojunction materials that were partially derived from CoFe-LDH. These materials synergistically interact with Ti3C2 MXene nanosheets facilitating multi-interface interactions. Indeed, the highest tetracycline hydrochloride degradation rate of nearly 92% in 2 h was achieved because of the intense synergy between the CoFe-LDH/CoFeCrO4 heterojunction material optimized with 7.5 wt.% of MXene nanosheets (CMC-7.5). This degradation performance was 3.1 times greater than that of the original CoFe-LDH. Further, CMC-7.5 produces the highest H2 gas of 458.79 μmol h−1g−1 from a photocatalytic water splitting reaction. The formation of a Schottky energy barrier between the partially derived CoFe-LDH/CoFeCrO4 unit and MXene promoted the fast transfer of photogenerated electrons from CoFe-LDH/CoFeCrO4 to the surface of MXene, thereby providing a plethora of active sites for photocatalytic reactions. Photoelectrochemical assessments using transient and linear sweep voltammetry along with electrochemical impedance spectroscopy confirmed efficient charge carrier transfer. Moreover, the optimized CMC-7.5 photoelectrode has a superior integral area and exhibited excellent stability over 100 cycles. Finally, the study outlines the construction of several advanced materials with multi-interface heterojunctions involving cation-exchanged LDH derivatives with high photogenerated charge carrier separation efficiency and minimal interfacial migration resistance to serve as stability benchmarks for practical applications.
在具有大量活性位点的结界面上建立有效的电荷转移通道,以提高半导体材料的光催化活性,是一项艰巨的挑战。在此,我们提出了一种基于原位水热法的新方法,用于合成 CoFe 层状双氢氧化物(LDH)/CoFeCrO4 异质结材料。这些材料与 Ti3C2 MXene 纳米片协同作用,促进了多界面相互作用。事实上,由于 CoFe-LDH/CoFeCrO4 异质结材料与 7.5 wt.% 的 MXene 纳米片(CMC-7.5)之间的强烈协同作用,盐酸四环素在 2 小时内的降解率最高,接近 92%。这种降解性能是原始 CoFe-LDH 的 3.1 倍。此外,CMC-7.5 在光催化水分离反应中产生的 H2 气体最高,达到 458.79 μmol h-1g-1。在部分衍生的 CoFe-LDH/CoFeCrO4 单元和 MXene 之间形成的肖特基能障促进了光生电子从 CoFe-LDH/CoFeCrO4 向 MXene 表面的快速转移,从而为光催化反应提供了大量的活性位点。使用瞬态和线性扫描伏安法以及电化学阻抗光谱法进行的光电化学评估证实了高效的电荷载流子转移。此外,优化后的 CMC-7.5 光电极具有优异的积分面积,在 100 次循环中表现出卓越的稳定性。最后,该研究概述了几种先进的多界面异质结材料的构造,这些材料涉及阳离子交换 LDH 衍生物,具有较高的光生电荷载流子分离效率和最小的界面迁移阻力,可作为实际应用的稳定性基准。
Dynamic and seismic response characteristics of above-ground flax fiber-reinforced epoxy pipes
Saeed Eyvazinejad Firouzsalari, Dmytro Dizhur, Krishnan Jayaraman, Jason Ingham
doi:10.1016/j.compositesb.2024.111426
地面亚麻纤维增强环氧树脂管道的动态和地震响应特性
Dynamic and seismic response characteristics of free-spanning flax fibre-reinforced epoxy (FFRE) pipes with various diameters of 38, 60, 100, 160, and 205 mm and different fabric layers of 2, 3, and 4 (thickness of 3.4 mm–6.65 mm), and a free span of 3870 mm were investigated experimentally and numerically. The FFRE pipes were subjected to harmonic ground motions with peak ground acceleration of 0.1g, 0.2g, and 0.3g, vibration frequency of 2, 3, and 4 HZ, and a duration of 40 s, and a record from the 2011 Christchurch earthquake when the pipe was empty, half-filled or completely-filled with water to establish the effect of peak ground acceleration, vibration frequency, pipe water content, diameter and thickness on pipe displacement, acceleration, strains, and internal pressure. FFRE pipes underwent larger displacements and strains and higher transverse accelerations when the pipe was completely-filled, while the pipe underwent higher vertical acceleration and higher internal pressure when the pipe was half-filled. The pipe strain increased by up to 719% by increasing the peak ground acceleration from 0.1g to 0.3g, up to 452% by increasing the vibration frequency from 2 to 4 Hz, and up to 1358% by increasing the pipe water content from empty to completely-filled. FFRE pipes remained below their material ultimate limits, and no service or structural failure in the form of seepage or excessive deformation was detected in the pipe body, indicating great potential for using FFRE pipes as an alternative option to conventional pipes at seismic zones.
实验和数值研究了自由跨度为 38、60、100、160 和 205 mm,织物层数为 2、3 和 4(厚度为 3.4 mm-6.65 mm),自由跨度为 3870 mm 的亚麻纤维增强环氧树脂(FFRE)管道的动态和地震响应特性。FFRE 管道承受了峰值地面加速度为 0.1g、0.2g 和 0.3g,振动频率为 2、3 和 4 HZ,持续时间为 40 秒的谐波地面运动,以及 2011 年基 督城地震中管道空载、半载或全载注水时的记录,以确定峰值地面加速度、振动频率、管道含水量、直径和厚度对管道位移、加速度、应变和内压的影响。当管道完全充满水时,FFRE 管道的位移和应变更大,横向加速度更高;而当管道半充满水时,管道的垂直加速度更高,内压更高。将地面加速度峰值从 0.1g 提高到 0.3g,管道应变最多可增加 719%;将振动频率从 2 Hz 提高到 4 Hz,管道应变最多可增加 452%;将管道含水量从空增加到完全充满,管道应变最多可增加 1358%。FFRE 管道的强度仍低于其材料极限,并且未发现管体出现渗水或过度变形等使用或结构故障,这表明在地震带使用 FFRE 管道作为传统管道的替代选择具有巨大潜力。