Superstructures

上层建筑
  • 文章类型: Journal Article
    涉及CO2升级转化的耦合电合成对环境和能源的可持续发展具有重要意义,但具有挑战性。在这里,我们从Cu(OH)2阵列结构前体精细构建了自支撑双金属阵列超结构,可以在阳极和阴极上实现甲酸盐和己二酸盐的高性能耦合电合成,分别。具体而言,在两个电极上,CO2至甲酸盐和环己酮至己二酸盐转化率的法拉第效率(FE)同时超过90%,具有出色的稳定性。这种高性能耦合电合成与CuBi合金作为阴极的多孔纳米片阵列超结构和CuNi氢氧化物作为阳极的纳米线上纳米片阵列超结构高度相关。此外,与传统的电解工艺相比,电池电压大幅降低,同时保持了双电极电解槽中耦合电合成的电催化性能,最大的FE甲酸酯和FEadipate高达94.2%和93.1%,分别。实验结果进一步表明,双金属成分调制了局部电子结构,促进对目标产品的反应。Prospective,我们的工作提出了一种指导性策略,用于构建自适应自支撑上层建筑以实现有效的耦合电合成。
    The coupling electrosynthesis involving CO2 upgrade conversion is of great significance for the sustainable development of the environment and energy but is challenging. Herein, we exquisitely constructed the self-supported bimetallic array superstructures from the Cu(OH)2 array architecture precursor, which can enable high-performance coupling electrosynthesis of formate and adipate at the anode and the cathode, respectively. Concretely, the faradaic efficiencies (FEs) of CO2-to-formate and cyclohexanone-to-adipate conversion simultaneously exceed 90% at both electrodes with excellent stabilities. Such high-performance coupling electrosynthesis is highly correlated with the porous nanosheet array superstructure of CuBi alloy as the cathode and the nanosheet-on-nanowire array superstructure of CuNi hydroxide as the anode. Moreover, compared to the conventional electrolysis process, the cell voltage is substantially reduced while maintaining the electrocatalytic performance for coupling electrosynthesis in the two-electrode electrolyzer with the maximal FEformate and FEadipate up to 94.2% and 93.1%, respectively. The experimental results further demonstrate that the bimetal composition modulates the local electronic structures, promoting the reactions toward the target products. Prospectively, our work proposes an instructive strategy for constructing adaptive self-supported superstructures to achieve efficient coupling electrosynthesis.
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  • 文章类型: Journal Article
    具有复杂分层空间配置的上层结构比单个分层结构具有更宽的结构深度和更广泛的应用前景。然而,目前的制备方法受到繁琐的步骤和苛刻的条件的极大限制。这里,我们呈现,第一次,一种简洁有效的热响应动态合成策略,用于在可溶性共价有机网络(SCONS)内制备多维复杂的超结构,具有从0D中空超颗粒到2D薄膜的可调形态。机理研究揭示了SCONS的热响应动态“裂解-重塑”特性,基于[2.2]对环烷独特的双层结构合成,和温度控制促进了从可逆溶解度到重组和构建上部结构的过程。具体来说,在这个过程中,油水乳液两相界面可以通过液滴喷射产生,导致制备0D中空超颗粒和其他碗状复杂超结构,产量高。此外,通过调节外源溶剂的挥发性和溶解度,基于气液界面制备了无缺陷的2D薄膜。扩展的实验进一步证实了所提出的动态“分裂-重塑”策略的普遍性和可扩展性。客体碘富集机理的研究突出了超结构产物相对于单层材料的优越的动力学传质性能。这项研究不仅为上层建筑的建设提供了一条创新的捷径,也是体现上层建筑优势及其广泛应用的科学依据。本文受版权保护。保留所有权利。
    Superstructures with complex hierarchical spatial configurations exhibit broader structural depth than single hierarchical structures and the associated broader application prospects. However, current preparation methods are greatly constrained by cumbersome steps and harsh conditions. Here, for the first time, a concise and efficient thermally responsive dynamic synthesis strategy for the preparation of multidimensional complex superstructures within soluble covalent organic networks (SCONs) with tunable morphology from 0D hollow supraparticles to 2D films is presented. Mechanism study reveals the thermally responsive dynamic \"cleavage-remodeling\" characteristics of SCONs, synthesized based on the unique bilayer structure of (2.2)paracyclophane, and the temperature control facilitates the process from reversible solubility to reorganization and construction of superstructures. Specifically, during the process, the oil-water-emulsion two-phase interface can be generated through droplet jetting, leading to the preparation of 0D hollow supraparticles and other bowl-like complex superstructures with high yield. Additionally, by modulating the volatility and solubility of exogenous solvents, defect-free 2D films are prepared relying on an air-liquid interface. Expanded experiments further confirm the generalizability and scalability of the proposed dynamic \"cleavage-remodeling\" strategy. Research on the enrichment mechanism of guest iodine highlights the superior kinetic mass transfer performance of superstructural products compared to single-hierarchical materials.
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  • 文章类型: Journal Article
    脊椎动物的光感受器细胞的超微结构膜散布有丰富的光敏离子泵,以促进信号产生并在昏暗的光线下实现高增益。鉴于此,开发了具有阳离子选择性纳米通道的超结构光离子异质结(SSOHs),用于操纵光驱动的离子泵浦。采用模板导向的自下而上策略,将氧化石墨烯(GO)和PEDOT:PSS顺序组装成具有雕刻超结构的异质膜,其特征是膜形貌的可编程变化,并包含能够在光照下保持电子-空穴分离的供体-受体界面。与具有平面配置的常规光离子膜相比,这种精心设计的设计为SSOH提供了更高的光驱动离子通量,以对抗浓度梯度。这可以归因于增强的跨膜电位的建立,这是由于在异质结界面处有效分离了光生载流子,并且由于反射减少的协同作用而增加了来自光照射的能量输入。广角吸收,和宽波段吸收。这项工作揭示了膜形貌在光驱动跨膜运输中的重要性,并提出了这样一个通用原型,可以扩展到其他光离子膜,以开发用于能量转换和传感的高性能人工离子泵。
    Photoreceptor cells of vertebrates feature ultrastructural membranes interspersed with abundant photosensitive ion pumps to boost signal generation and realize high gain in dim light. In light of this, superstructured optoionic heterojunctions (SSOHs) with cation-selective nanochannels are developed for manipulating photo-driven ion pumping. A template-directed bottom-up strategy is adopted to sequentially assemble graphene oxide (GO) and PEDOT:PSS into heterogeneous membranes with sculptured superstructures, which feature programmable variation in membrane topography and contain a donor-acceptor interface capable of maintaining electron-hole separation upon photoillumination. Such elaborate design endows SSOHs with a much higher magnitude of photo-driven ion flux against a concentration gradient in contrast to conventional optoionic membranes with planar configuration. This can be ascribed to the buildup of an enhanced transmembrane potential owing to the effective separation of photogenerated carriers at the heterojunction interface and the increase of energy input from photoillumination due to a synergistic effect of reflection reduction, broad-angle absorption, and wide-waveband absorption. This work unlocks the significance of membrane topographies in photo-driven transmembrane transportation and proposes such a universal prototype that could be extended to other optoionic membranes to develop high-performance artificial ion pumps for energy conversion and sensing.
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  • 文章类型: Journal Article
    无机纳米晶体的自组装为功能材料的制备提供了有效的途径。然而,构造具有可控形状的多维纳米结构仍然具有挑战性,组成和功能。这里,通过多金属氧酸盐(POM)团簇的表面改性,开发了一系列不同尺寸的异质结构。三种POM团簇(磷钼酸(PMA),磷钨酸(PTA)和硅钨酸(STA)及五种金属氧化物(TiO2,VOx,La2O3,In2O3和Gd2O3)可以用作构建块,和一类1D,2D和3D异质结构可以通过控制表面配体覆盖来实现。与单个构建块和其他基于集群的上层建筑相比,TiO2-PMA超结构对硫醚氧化表现出增强的催化活性,这归因于TiO2和POM团簇之间的电子转移。
    The self-assembly of inorganic nanocrystals offers an efficient way for the fabrication of functional materials. However, it is still challenging for the construction of multidimensional nanostructures with controllable shapes, compositions and functions. Here, a series of heterostructures in different dimensions by surface modification of polyoxometalate (POM) clusters is developed. Three kinds of POM clusters (phosphomolybdic acid (PMA), phosphotungstic acid (PTA) and silicotungstic acid (STA) and five kinds of metal oxides (TiO2 , VOx , La2 O3 , In2 O3 and Gd2 O3 ) can be used as building blocks, and a class of 1D, 2D and 3D heterostructures can be achieved by the control of surface ligand coverage. Compared with individual building blocks and other cluster-based superstructures, TiO2 -PMA superstructures exhibit enhanced catalytic activity toward thioether oxidations, which is attributed to the electron transfer between TiO2 and POM clusters.
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  • 文章类型: Journal Article
    液晶(LC)的螺旋扭曲倾向通常由手性发射体的固有构型控制。这里,我们通过控制单个对映体发射体(R-PCP)与LC单体(5CB)的比例,引入了超分子手性以及圆偏振发光(CPL)的多级反转。将R-PCP的含量从1wt%增加到3wt%,使LC的螺旋从左手到右手,伴随的CPL信号从正变为负。手性发射体的双轴性,以及手性-手性和手性-非手性相互作用的空间效应,被确定为螺旋感觉倒置的原因。由于强大的螺旋扭转力,4wt%R-PCP驱动手性LC的光子带隙(PBG)与它们的发射范围相匹配,导致CPL再次反转,具有较高的不对称因子(~1.2)。在胆甾型LC中很少实现使用手性发射体直接调节PBG。在此基础上,将非手性敏化剂PtTPBP组装到螺旋上层结构中。通过调节PBG的位置,在单个手性LC系统中实现了从R-PCP产生三重态-三重态an灭诱导的上转换CPL和从PtTPBP产生相反旋转的下转换CPL。
    The helical twisting tendency of liquid crystals (LCs) is generally governed by the inherent configuration of the chiral emitter. Here, we introduce the multistage inversion of supramolecular chirality as well as circularly polarized luminescence (CPL) by manipulating the ratio of single enantiomeric emitters (R-PCP) to LC monomers (5CB). Increasing the content of R-PCP from 1 wt % to 3 wt % inverted the helix of LCs from left-handed to right-handed, accompanying a CPL sign changed from positive to negative. The biaxiality of chiral emitters, as well as the steric effect of chiral-chiral and chiral-achiral interaction, were identified as the reasons for helical sense inversion. Due to the strong helical twisting power, 4 wt % R-PCP drove the photonic band gap (PBG) of chiral LCs to match up with their emission range, leading to an inversion of the CPL again with a high dissymmetry factor (≈1.2). Directly adjusting the PBG using chiral emitters is seldom achieved in cholesteric LCs. On this basis, an achiral sensitizer PtTPBP was assembled into the helical superstructure. The generation of triplet-triplet annihilation-induced upconverted CPL from R-PCP and the downshifting CPL from PtTPBP with opposite rotation was achieved in a single chiral LC system by tuning the position of the PBG.
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  • 文章类型: Journal Article
    由纳米晶体(NC)组成的自组装超结构显示出提高电催化应用性能的巨大潜力。然而,关于将铂(Pt)自组装成低维超结构作为氧还原反应(ORR)的有效电催化剂的研究有限。在这项研究中,我们使用模板辅助外延组装方法设计了由单层或亚单层碳铠装铂纳米晶体(PtNC)组成的独特管状上部结构。PtNCs表面的有机配体被原位碳化,产生包裹PtNCs的少层石墨碳壳。由于它们的单层组装和管状几何形状,超管的Pt利用率是常规碳负载PtNC的1.5倍。因此,这种Pt超管在酸性介质中对ORR表现出显著的电催化性能,具有0.918V的高半波电位和0.9V时181Ag-1Pt的高质量活性,其与商业碳负载的Pt(Pt/C)催化剂相当。此外,Pt超管表现出强大的催化稳定性,通过长期加速耐久性测试和相同位置透射电子显微镜证实。这项研究提出了一种设计Pt超结构以实现高效和稳定电催化的新方法。
    Self-assembled superstructures composed of nanocrystals (NCs) have shown immense potential for enhancing the performance in electrocatalytic applications. However, there has been limited research on the self-assembly of platinum (Pt) into low-dimensional superstructures as efficient electrocatalysts for oxygen reduction reaction (ORR). In this study, we designed a unique tubular superstructure composed of monolayer or sub-monolayer carbon-armored platinum nanocrystals (Pt NCs) using a template-assisted epitaxial assembly approach. The organic ligands on the surface of Pt NCs were in situ carbonized, resulting in few-layer graphitic carbon shells that encapsulate Pt NCs. Due to their monolayer assembly and tubular geometry, the Pt utilization of the supertubes was 1.5 times higher than that of conventional carbon-supported Pt NCs. As a result, such Pt supertubes exhibit remarkable electrocatalytic performance for the ORR in acidic media, with a high half-wave potential of 0.918 V and a high mass activity of 181 A g-1Pt at 0.9 V, which are comparable to commercial carbon-supported Pt (Pt/C) catalysts. Furthermore, the Pt supertubes demonstrate robust catalytic stability, as confirmed by long-term accelerated durability tests and identical-location transmission electron microscopy. This study presents a new approach to designing Pt superstructures for highly efficient and stable electrocatalysis.
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  • 文章类型: Journal Article
    开发用于整体水分解的廉价双功能电催化剂对于获得可扩展的绿色氢并由此实现碳中和至关重要。在这里,开发了一种“多合一”方法,用于制造具有分层结构的高N掺杂二元FeCo磷化物(N-FeCoP),这种精心设计的合成路线允许以下优点有利于水裂解电催化在碱性,包括高N/缺陷掺杂,以调节制成的N-FeCoP的表面性能,二元Fe和Co组分表现出强耦合相互作用,和3D分层上层结构,以缩短扩散长度,从而改善反应动力学。电化学测量表明,N-FeCoP样品表现出非常低的超电势,用于引发氢和氧析出反应。值得注意的是,可以使用商业初级Zn-MnO2电池在N-FeCoP上促进总体水分解。所开发的合成策略可能潜在地激发用于广泛电催化的其他N掺杂金属基纳米结构的制备。
    Developing an inexpensive bifunctional electrocatalyst for overall water splitting is critical for acquiring scalable green hydrogen and thereby realizing carbon neutralization. Herein, an \"all-in-one\" method is developed for the fabrication of highly N-doped binary FeCo-phosphides (N-FeCoP) with hierarchical superstructure, this delicately designed synthesis route allows the following merits for benefiting water splitting electrocatalysis in alkaline, including high N/defect-doping for mediating the surface property of the as-made N-FeCoP, binary Fe and Co components exhibiting strong coupling interaction, and 3D hierarchical superstructure for shortening diffusion length and thereby improving reaction kinetics. Electrochemical measurements reveal that the N-FeCoP sample exhibits very low overpotentials for initiating the hydrogen and oxygen evolution reactions. Remarkably, overall water splitting can be promoted on N-FeCoP using a commercial primary Zn-MnO2 battery. The developed synthesis strategy may potentially inspire the preparation of other N-doped metal-based nanostructures for broad electrocatalysis.
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  • 文章类型: Journal Article
    All inorganic CsPbBr3 superstructures (SSs) have attracted much research interest due to their unique photophysical properties, such as their large emission red-shifts and super-radiant burst emissions. These properties are of particular interest in displays, lasers and photodetectors. Currently, the best-performing perovskite optoelectronic devices incorporate organic cations (methylammonium (MA), formamidinium (FA)), however, hybrid organic-inorganic perovskite SSs have not yet been investigated. This work is the first to report on the synthesis and photophysical characterization of APbBr3 (A = MA, FA, Cs) perovskite SSs using a facile ligand-assisted reprecipitation method. At higher concentrations, the hybrid organic-inorganic MA/FAPbBr3 nanocrystals self-assemble into SSs and produce red-shifted ultrapure green emissions, meeting the requirement of Rec. 2020 displays. We hope that this work will be seminal in advancing the exploration of perovskite SSs using mixed cation groups to further improve their optoelectronic applications.
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  • 文章类型: Journal Article
    在环境条件下合成NH3的电催化氮还原反应(NRR)是常规Haber-Bosch工艺的有希望的替代路线,但开发高法拉第效率和氨产率的电催化剂仍然是一个巨大的挑战。在这里,一种通过金属有机框架(MOF)衍生的范德华超结构合成超薄2D硼和氮共掺杂多孔碳纳米片(B/NCNS)的简便有效的剥离策略,据报道。实验和理论计算结果表明,硼和氮的掺杂可以调节相邻碳原子的电子结构,促进氮的竞争性吸附,减少氨合成所需的能量。B/N+CNS在电催化NRR中表现出优异的催化性能和稳定性,产率为153.4µg·h-1·mg-1cat,法拉第效率为33.1%,这优于大多数报道的NRR电催化剂。在48h稳定性试验后,B/N和CNS的氨产率可以保持初始NRR活性的92.7%。作者使用MOF衍生的范德华超结构的可控剥离策略可以为其他2D材料的合成提供新的见解。
    The electrocatalytic nitrogen reduction reaction (NRR) to synthesize NH3 under ambient conditions is a promising alternative route to the conventional Haber-Bosch process, but it is still a great challenge to develop electrocatalysts\' high Faraday efficiency and ammonia yield. Herein, a facile and efficient exfoliation strategy to synthesize ultrathin 2D boron and nitrogen co-doped porous carbon nanosheets (B/NC NS) via a metal-organic framework (MOF)-derived van der Waals superstructure, is reported. The results of experiments and theoretical calculations show that the doping of boron and nitrogen can modulate the electronic structure of the adjacent carbon atoms; which thus, promotes the competitive adsorption of nitrogen and reduces the energy required for ammonia synthesis. The B/NC NS exhibits excellent catalytic performance and stability in electrocatalytic NRR, with a yield rate of 153.4 µg·h-1 ·mg-1 cat and a Faraday efficiency of 33.1%, which is better than most of the reported NRR electrocatalysts. The ammonia yield of B/NC NS can maintain 92.7% of the initial NRR activity after 48 h stability test. The authors\' controllable exfoliation strategy using MOF-derived van der Waals superstructure can provide a new insight for the synthesis of other 2D materials.
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  • 文章类型: Journal Article
    纤维状储能装置是可穿戴和便携式电子产品的不可缺少的部分。水性可充电Ni/Fe电池由于其良好的安全性而无需有机电解质,因此是一种非常合适的储能设备,高离子电导率,和低成本。不幸的是,低能量密度,差的功率密度和循环性能阻碍了其进一步的实际应用。在这项研究中,为了获得高性能的负极铁基材料,我们首先在高导电碳纳米管纤维(CNTFs)表面合成了具有超结构的α-氧化铁(α-Fe2O3)纳米棒(NRs),然后涂覆导电聚吡咯(PPy)以增强电子,离子扩散和循环稳定性。制备的α-Fe2O3@PPyNRs/CNTF电极在1Acm-3的电流密度下显示出0.62Ahcm-3的高比容量。此外,由上述负极组装的Ni/Fe电池在1Acm-3的电流密度下显示出最大体积能量密度为15.47mWhcm-3和228.2mwcm-3。测试了Ni/Fe电池的循环耐久性和机械柔性,具有良好的实际应用前景。总之,这些优点使我们的Ni/Fe电池有可能在下一代柔性储能设备中实际应用。
    Fiber-shaped energy storage devices areindispensableparts of wearable and portable electronics. Aqueous rechargeable Ni/Fe battery is a very appropriate energy storage device due to their good safety without organic electrolytes, high ionic conductivity, and low cost. Unfortunately, the low energy density, poor power density and cycling performance hinder its further practical applications. In this study, in order to obtain high performance negative iron-based material, we first synthesized α-iron oxide (α-Fe2O3) nanorods (NRs) with superstructures on the surface of highly conductive carbon nanotube fibers (CNTFs), then electrically conductive polypyrrole (PPy) was coated to enhance the electron, ion diffusion and cycle stability. Theas-prepared α-Fe2O3@PPy NRs/CNTF electrode shows a high specific capacity of 0.62 Ah cm-3 at the current density of 1 A cm-3. Furthermore, the Ni/Fe battery that was assembled by the above negative electrode shows a maximum volumetric energy density of 15.47 mWh cm-3 with 228.2 mW cm-3 at a current density of 1 A cm-3. The cycling durability and mechanical flexibility of the Ni/Fe battery were tested, which show good prospect for practical application. In summary, these merits make it possible for our Ni/Fe battery to have practical applications in next generation flexible energy storage devices.
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