Recent Submissions

  • Bioprospecting of Novel Extremozymes From Prokaryotes-The Advent of Culture-Independent Methods.

    Sysoev, Maksim; Grötzinger, Stefan W.; Renn, Dominik; Eppinger, Jörg; Rueping, Magnus; Karan, Ram (Frontiers in microbiology, Frontiers Media SA, 2021-03-01) [Article]
    Extremophiles are remarkable organisms that thrive in the harshest environments on Earth, such as hydrothermal vents, hypersaline lakes and pools, alkaline soda lakes, deserts, cold oceans, and volcanic areas. These organisms have developed several strategies to overcome environmental stress and nutrient limitations. Thus, they are among the best model organisms to study adaptive mechanisms that lead to stress tolerance. Genetic and structural information derived from extremophiles and extremozymes can be used for bioengineering other nontolerant enzymes. Furthermore, extremophiles can be a valuable resource for novel biotechnological and biomedical products due to their biosynthetic properties. However, understanding life under extreme conditions is challenging due to the difficulties of in vitro cultivation and observation since > 99% of organisms cannot be cultivated. Consequently, only a minor percentage of the potential extremophiles on Earth have been discovered and characterized. Herein, we present a review of culture-independent methods, sequence-based metagenomics (SBM), and single amplified genomes (SAGs) for studying enzymes from extremophiles, with a focus on prokaryotic (archaea and bacteria) microorganisms. Additionally, we provide a comprehensive list of extremozymes discovered via metagenomics and SAGs.
  • Superconductivity and High-Pressure Performance of 2D Mo2C Crystals

    Zhang, Junli; Cao, Zhen; He, Xin; Liu, Wenhao; Wen, Yan; Cavallo, Luigi; Ren, Wencai; Cheng, Huiming; Zhang, Xixiang (The Journal of Physical Chemistry Letters, American Chemical Society (ACS), 2021-02-26) [Article]
    Two-dimensional (2D) materials have attracted significant attention for their ability to support novel magneto-electrical transport and their optical and magnetic properties, of which their superconductivity is particularly of interest. Here we report on the behavior of superconductivity in 2D Mo2C crystals when hydrostatic pressure is applied, which has not yet been described in the literature. We found that the localization of boundary atoms disorder-induced Cooper pairs can suppress the superconducting transition temperature (Tc) as effectively as a magnetic field and current. We observed that the Tc initially decreased as the pressure increased to 1.75 GPa but then began to increase as the pressure increased further to 2.5 GPa. Our density functional theory calculations revealed that this behavior was linked to the modulation of the strength of the electron-phonon coupling and the electron property, which was triggered by compression of the lattice under high pressure. We attributed the inflection point in the hydrostatic pressure-dependent Tc curve to the structural phase transition of Mo2C from a hexagonal to an orthorhombic structure. This work presents a new avenue for the study of the superconductivity of Mo2C, which can be extended to apply to other 2D superconductors to modulate their electronic states.
  • Layer number dependent ferroelasticity in 2D Ruddlesden–Popper organic-inorganic hybrid perovskites

    Xiao, Xun; Zhou, Jian; Song, Kepeng; Zhao, Jingjing; Zhou, Yu; Rudd, Peter Neil; Han, Yu; Li, Ju; Huang, Jinsong (Nature Communications, Springer Science and Business Media LLC, 2021-02-26) [Article]
    AbstractFerroelasticity represents material domains possessing spontaneous strain that can be switched by external stress. Three-dimensional perovskites like methylammonium lead iodide are determined to be ferroelastic. Layered perovskites have been applied in optoelectronic devices with outstanding performance. However, the understanding of lattice strain and ferroelasticity in layered perovskites is still lacking. Here, using the in-situ observation of switching domains in layered perovskite single crystals under external strain, we discover the evidence of ferroelasticity in layered perovskites with layer number more than one, while the perovskites with single octahedra layer do not show ferroelasticity. Density functional theory calculation shows that ferroelasticity in layered perovskites originates from the distortion of inorganic octahedra resulting from the rotation of aspherical methylammonium cations. The absence of methylammonium cations in single layer perovskite accounts for the lack of ferroelasticity. These ferroelastic domains do not induce non-radiative recombination or reduce the photoluminescence quantum yield.
  • Effect of Zinc-doping on the Reduction of the Hot-carrier Cooling Rate in Halide Perovskites

    Xing, Guichuan; WEI, Qi; Yin, Jun; Bakr, Osman; Wang, Ze; Wang, Chenhao; Mohammed, Omar F.; Li, Mingjie (Angewandte Chemie, Wiley, 2021-02-25) [Article]
    Fast hot-carrier cooling process in the solar-absorbers fundamentally limits the photon-energy conversion efficiencies. It is highly desirable to develop the solar absorber with long-lived hot-carriers at sun-illumination level, which can be used to develop the hot-carrier solar cells with enhanced efficiency. Herein, we reveal that zinc-doped (0.34%) halide perovskites have the slower hot-carrier cooling compared with the pristine sample through the transient absorption spectroscopy measurements and theoretical calculations. The hot-carrier energy loss rate at the low photoexcitation level of 10 17 cm -3 is found to be ~3 times smaller than that of un-doped perovskites for 500-K hot carriers, and up to ten times when the hot-carrier temperature approaching the lattice temperature. The incorporation of zinc-dopant into perovskites can reduce the nonadiabatic couplings between conduction bands, which retards the photogenerated hot-carriers relaxation process. Our findings present a practical strategy to slow down the hot-carrier cooling in perovskites at low carrier densities, which are valuable for the further development of practical perovskite hot-carrier photovoltaics .
  • Single-Crystalline Ultrathin 2D Porous Nanosheets of Chiral Metal–Organic Frameworks

    Liu, Yuhao; Liu, L. M.; Chen, Xu; Liu, Yan; Han, Yu; Cui, Yong (Journal of the American Chemical Society, American Chemical Society (ACS), 2021-02-23) [Article]
    Two-dimensional (2D) materials with highly ordered in-plane nanopores are crucial for numerous applications, but their rational synthesis and local structural characterization remain two grand challenges. We illustrate here that single-crystalline ultrathin 2D MOF nanosheets (MONs) with intrinsic porosity can be prepared by exfoliating layered metal-organic frameworks (MOFs), whose layers are stabilized by sterically bulky groups. As a result, three three-dimensional (3D) isostructural lanthanide MOFs possessing porous layer structures are constructed by coordinating metal ions with an angular dicarboxylate linker derived from chiral 1,1'-biphenyl phosphoric acid with pendant mesityl groups. The Eu-MOF is readily ultrasonic exfoliated into single-crystalline nanosheets with a thickness of ca. 6.0 nm (2 layers) and a lateral size of 1.5 × 3.0 μm2. The detailed structural information, i.e., the pore channels and individual organic and inorganic building units in the framework, is clearly visualized by a low-dose high-resolution transmission electron microscopy (HRTEM) technique. Benefiting from their ultrathin feature, the nanosheets are well embedded into the polymer matrix to form free-standing mixed-matrix membranes. In both the solution and membrane phase, the fluorescence of the MONs can be effectively quenched by a total of 17 chiral terpenes and terpenoids through supramolecular interactions with uncoordinated chiral phosphoric acids, leading to a chiral optical sensor for detecting vapor enantiomers, which is among the most challenging molecular recognition tasks.
  • Replacing Thymine with a Strongly Pairing Fifth Base: a Combined Quantum Mechanics and Molecular Dynamics Study

    Chawla, Mohit; Gorle, Suresh; Shaikh, Abdul Rajjak; Oliva, Romina; Cavallo, Luigi (Computational and Structural Biotechnology Journal, Elsevier BV, 2021-02-23) [Article]
    The non-natural ethynylmethylpyridone C-nucleoside (W), a thymidine (T) analogue that can be incorporated in oligonucleotides by automated synthesis, has recently been reported to form a high fidelity base pair with adenosine (A) and to be well accommodated in B-DNA duplexes. The enhanced binding affinity for A of W, as compared to T, makes it an ideal modification for biotechnological applications, such as efficient probe hybridization for the parallel detection of multiple DNA strands. In order to complement the experimental study and rationalize the impact of the non-natural W nucleoside on the structure, stability and dynamics of DNA structures, we performed quantum mechanics (QM) calculations along with molecular dynamics (MD) simulations. Consistently with the experimental study, our QM calculations show that the A:W base pair has an increased stability as compared to the natural A:T pair, due to an additional CH-π interaction. Furthermore, we show that mispairing between W and guanine (G) causes a distortion in the planarity of the base pair, thus explaining the destabilization of DNA duplexes featuring a G:W pair. MD simulations show that incorporation of single or multiple consecutive A:W pairs in DNA duplexes causes minor changes to the intra- and inter-base geometrical parameters, while a moderate widening/shrinking of the major/minor groove of the duplexes is observed. QM calculations applied to selected stacks from the MD simulations also show an increased stacking energy for W, over T, with the neighboring bases.
  • CsMnBr3: Lead-Free Nanocrystals with High Photoluminescence Quantum Yield and Picosecond Radiative Lifetime

    Almutlaq, Jawaher; Mir, Wasim Jeelani; Gutierrez Arzaluz, Luis; Yin, Jun; Vasylevskyi, Serhii; Maity, Partha; Liu, Jiakai; Naphade, Rounak; Mohammed, Omar F.; Bakr, Osman (ACS Materials Letters, American Chemical Society (ACS), 2021-02-15) [Article]
    Lead halide compounds, including lead halide perovskite nanocrystals (NCs), have attracted the interest of researchers in optoelectronics and photonics because of their high photoluminescence quantum yields (PLQYs) coupled with relatively short PL lifetimes (on the order of a few nanoseconds). However, lead-free metal halides of high PLQY, including double perovskites and their doped NCs, typically possess long PL lifetimes (up to microseconds) that limit their application space. Here, we introduce CsMnBr3 NCs, which are lead-free and red-emitting, that combine a high PLQY with an exceptionally short radiative lifetime (on the order of picoseconds). We find that the octahedral coordination of Mn2+ in CsMnBr3 induces a red emission centered at ∼643 nm with a PLQY of ∼54% and a fast radiative decay rate. Femtosecond transient absorption and transient PL spectroscopies reveal the existence of a low-lying excited state of Mn2+ that relaxes to the ground state within around 605 ps by emitting light at around 643 nm. At greater excitation energies, higher excited states of Mn2+ relax in the sub-nanosecond time scale to this low-lying excited state. A similarly positioned PL peak with a short picosecond scale PL lifetime and a PLQY of ∼6.7% was also detected in bulk CsMnBr3 single crystals reported in this study—a relatively high quantum yield for a bulk material. Our experimental results and density functional theory modelling show that the crystal structure and the strong coupling among Mn2+ ions govern those luminescence properties of CsMnBr3 NCs and single crystals. These findings pave the way for new lead-free materials that combine high PLQY and ultrafast luminescence.
  • Domain-Size-Dependent Residual Stress Governs the Phase-Transition and Photoluminescence Behavior of Methylammonium Lead Iodide

    Lee, Kwangjae; Turedi, Bekir; Giugni, Andrea; Lintangpradipto, Muhammad Naufal; Zhumekenov, Ayan A.; Alsalloum, Abdullah; Min, Jung-Hong; Dursun, Ibrahim; Naphade, Rounak; Mitra, Somak; Roqan, Iman S.; Ooi, Boon S.; Mohammed, Omar F.; Di Fabrizio, Enzo M.; Cho, Namchul; Bakr, Osman (Advanced Functional Materials, Wiley, 2021-02-11) [Article]
    Methylammonium lead iodide (MAPbI3) perovskite has garnered significant interest as a versatile material for optoelectronic applications. The temperature-dependent photoluminescence (TDPL) and phase-transition behaviors revealed in previous studies have become standard indicators of defects, stability, charge carrier dynamics, and device performance. However, published reports abound with examples of irregular photoluminescence and phase-transition phenomena that are difficult to reconcile, posing major challenges in the correlation of those properties with the actual material state or with the subsequent device performance. In this paper, a unifying explanation for the seemingly inconsistent TDPL and phase-transition (orthorhombic-to-tetragonal) characteristics observed for MAPbI3 is presented. By investigating MAPbI3 perovskites with varying crystalline states, ranging from polycrystal to highly oriented crystal as well as single-crystals, key features in the TDPL and phase-transition behaviors are identified that are related to the extent of crystal domain-size-dependent residual stress and stem from the considerable volume difference (ΔV ≈ 4.5%) between the primitive unit cells of the orthorhombic (at 80 K) and tetragonal phases (at 300 K) of MAPbI3. This fundamental connection is essential for understanding the photophysics and material processing of soft perovskites.
  • Aromaticity in catalysis: metal ligand cooperation via ligand dearomatization and rearomatization

    Huang, Kuo-Wei; Goncalves, Theo; Dutta, Indranil (Chemical Communications, Royal Society of Chemistry (RSC), 2021-02-09) [Article]
    Unlike the conventional model of transition metal catalysis, ligands in metal–ligand cooperative (or bifunctional) catalysis are involved in the substrate activations. Such processes have offered unique mechanistic understandings and led...
  • Design, scope and mechanism of highly active and selective chiral NHC–iridium catalysts for the intramolecular hydroamination of a variety of unactivated aminoalkenes

    Foster, Daven; Gao, Pengchao; Zhang, Ziyun; Sipos, Gellért; Sobolev, Alexandre N.; Nealon, Gareth; Falivene, Laura; Cavallo, Luigi; Dorta, Reto (Chemical Science, Royal Society of Chemistry (RSC), 2021-02-04) [Article]
    Chiral, cationic NHC–iridium complexes are introduced as catalysts for the intramolecular hydroamination reaction of unactivated aminoalkenes.
  • Coordination-based self-assembled capsules (SACs) for protein, CRISPR–Cas9, DNA and RNA delivery

    Alimi, Lukman Olawale; Alyami, Mram Z.; Chand, Santanu; Baslyman, Walaa; Khashab, Niveen M. (Chemical Science, Royal Society of Chemistry (RSC), 2021-02-01) [Article]
    SACs can be efficiently used to load biologics such as proteins, CRISPR–Cas9, DNA and RNA and release them on-demand.
  • Penetrant competition and plasticization in membranes: How negatives can be positives in natural gas sweetening

    Liu, Yang; Chen, Zhijie; Qiu, Wulin; Liu, Gongping; Eddaoudi, Mohamed; Koros, William J. (Journal of Membrane Science, Elsevier BV, 2021-02) [Article]
    Membranes are attractive for upgrading natural gas; however, the gas permeation processes through membranes are challenging to control. The coexistence of condensable H2S and CO2 typically causes membrane performance to decline under practical feed conditions, due to uncontrolled penetrate competition and undesired plasticization of the membrane polymer matrix. In this paper, we report a strategy to successfully transform these apparent negatives, i.e. plasticization and penetrate competition, into positives that boost the natural gas sweetening efficiency of membranes greatly. Our strategy is to disperse engineered metal organic framework (MOF) fillers into designed polymer matrices to form hybrid membranes, which promote the permeation of both H2S and CO2 but hinder CH4 permeation. Moreover, uniformly dispersed MOF fillers also significantly alter the plasticization responses of polymer matrices, enabling controlled plasticization benefits. Ultimately, we illustrate a highly tunable MOF-polymer hybrid membrane platform that meets the diverse natural gas sweetening requirements under aggressive conditions.
  • Exploring the Reactivity of Well-defined Oxide-supported Metal­Alkyl and Alkylidyne Complexes via Surface Organometallic Chemistry

    Saidi, Aya (2021-02) [Dissertation]
    Advisor: Basset, Jean-Marie
    Committee members: Huang, Kuo-Wei; Saikaly, Pascal; Astruc, Didier
    Surface Organometallic Chemistry (SOMC) is an excellent approach to erase the gap between homogeneous and heterogeneous catalysis by grafting the molecular organometallic complex on various oxide surfaces, forming well-defined and single-site catalysts. This strategy allows for better characterization as well as the improvement and development of existing and new catalysts. These surface species could promote a wide range of catalytic applications (i.e., metathesis of hydrocarbons, hydrogenolysis of alkanes, and olefin polymerization reactions) depending on the metal center and its coordination sphere. In particular, the grafting of alkylated organometallic complexes of groups 4, 5, and 6 metals on the surface oxide is a thermodynamically favored reaction generally leading to strongly bonded well-defined surface species, which are highly reactive catalysts. This thesis has focused on the preparation, characterization, and catalytic investigation of different supported complexes that contain methyl, alkyl, and alkylidyne ligands. The first part compares the catalytic activity of [(≡Si−O−)W(-CH3)5] and [(≡Si-O-)Mo(≡CtBu)(-CH2tBu)2] surface species experimentally and by DFT calculations in the metathesis reactions of linear classical and functionalized olefins. Both pre-catalysts perform almost equally in the α-olefin metathesis reaction. However, in the functionalized olefin metathesis reaction, W pre-catalyst provides selective metathesis products and performs much better than Mo that gives a range of isomerization products. The second part deals with the synthesis and characterization of [(THF)2Zr(-CH3)4] and its grafting on silica support for the first time. The generated surface species [(≡Si−O−)Zr(CH3)3(THF)2] and [(≡Si−O−)2Zr(CH3)2(THF)2] are used for the conversion of CO2 and propylene oxide to cyclic propylene carbonates achieving a TON of 4227. The third part describes the first synthesis and characterization of the highly unstable homoleptic [Ti(-CH3)4] without any coordinating solvent. This complex was stabilized by grafting on SiO2-700, yielding two fully characterized surface species [(≡Si-O-)TiMe3] and [(≡Si-O-Si≡)(≡Si-O-)TiMe3], which were used in the hydrogenolysis reaction of propane and n-butane, with TONs of 419 and 578, respectively. Finally, the fourth part reports the immobilization and characterization of [TiMe2Cl2], an intermediate in the synthesis of [Ti(-CH3)4], on SiO2-700 resulting in [(≡Si-O-)TiMeCl2] and [(≡Si-O-)TiMe2Cl] surface species. These complexes reacted with a demethylating Lewis acid agent (BARF), forming the corresponding cationic Ti species [(≡Si-O-)TiMeCl]+ and [(≡Si-O-)TiCl2]+. Both neutral and cationic complexes were tested in the ethylene polymerization reaction affording linear HDPE with high molecular weights of 500,367 and 486,612 g/mol.
  • Metal Halide Perovskites for X-ray Imaging Scintillators and Detectors

    Zhou, Yang; Chen, Jie; Bakr, Osman; Mohammed, Omar F. (ACS Energy Letters, American Chemical Society (ACS), 2021-01-29) [Article]
    Radiation detection, using materials to convert high-energy photons to low-energy photons (X-ray imaging) or electrical charges (X-ray detector), has become essential for a wide range of applications including medical diagnostic technologies, computed tomography, quality inspection and security, etc. Metal halide perovskite-based high-resolution scintillation-imaging screens or direct conversion detectors are promising candidates for such applications, because they have high absorption cross sections for X-rays due to their heavy atom (e.g., Pb2+, Bi3+, I–) compositions; moreover, these materials are solution-processable at low temperature, possessing tunable bandgaps, near-unity photoluminescence quantum yields, low trap density, high charge carrier mobility, and fast photoresponse. In this review, we explore and decipher the working mechanism of scintillators and direct conversion detectors as well as the key advantages of halide perovskites for both detection approaches. We further discuss the recent advancements in this promising research area, pointing out the remaining challenges and our perspective for future research directions toward perovskite-based X-ray applications.
  • Air Stable Iridium Catalysts for Direct Reductive Amination of Ketones.

    Polishchuk, Iuliia; Sklyaruk, Jan; Lebedev, Yury; Rueping, Magnus (Chemistry (Weinheim an der Bergstrasse, Germany), Wiley, 2021-01-28) [Article]
    Half-sandwich iridium complexes bearing bidentate urea-phosphorus ligands were found to catalyze the direct reductive amination of aromatic and aliphatic ketones under mild conditions at 0.5 mol.% loading with high selectivity towards primary amines. One of the complexes was found to be active in both the Leuckart-Wallach (NH4CO2H) type reaction as well as in the hydrogenative (H2/NH4AcO) reductive amination. The protocol with ammonium formate does not require an inert atmosphere, dry solvents, as well as additives and in contrast to previous reports takes place in HFIP instead of methanol. Applying NH4CO2D or D2 resulted in a high degree of deuterium incorporation into the primary amine α-position.
  • Ultrafast Energy Transfer Triggers Ionization Energy Offset Dependence of Quantum Efficiency in Low-bandgap Non-fullerene Acceptor Solar Cells

    Gorenflot, Julien; Laquai, Frédéric; Firdaus, Yuliar; De Castro, Catherine S. P.; Harrison, George; Khan, Jafar Iqbal; Markina, Anastasia; Balawi, Ahmed; Dela Peña, Top Archie; Liu, Wenlan; Liang, Ru-Ze; Sharma, Anirudh; Karuthedath, Safakath; Zhang, Weimin; Lin, Yuanbao; Alarousu, Erkki; Anjum, Dalaver H.; Beaujuge, Pierre; De Wolf, Stefaan; McCulloch, Iain; Anthopoulos, Thomas D.; Baran, Derya; Andrienko, Denis; Paleti, Sri Harish Kumar (Fundació Scito, 2021-01-25) [Presentation]
    In bulk heterojunction (BHJ) solar cells, the heterojunction interface between electron donor and acceptor drives the exciton-to-charge conversion, yet it also adds to energy and carrier losses. In principle, in low-bandgap non-fullerene acceptor (NFA) BHJs both electron affinity (EA) and ionization energy (IE) offsets should equally control the internal quantum efficiency (IQE). Allegedly, exciton-to-charge conversion is efficient even for close-to-zero offsets. Here, we rebut both notions and demonstrate that counterintuitively, the charge transfer from the exciton rather than the further charge separation is the limiting step controlled by the IE offset and secondly, that sizeable IE offsets are required to reach high exciton-to charge conversion efficiency. We find that efficient Förster Resonant Energy Transfer to the low bandgap acceptor precedes the charge transfer, which thus always occurs via hole transfer from the acceptor, hence the unimportance of the EA offset. We discuss the reasons for the threshold IE offset in terms of interface energetics and find that two physical parameters are sufficient to describe the evolution of the IQE with IE offset on a very large range of material systems. Our model also explain other experimental observations such as the difficulty of observing CT states emission and absorption in NFA based systems.
  • Sustained and targeted delivery of checkpoint inhibitors by metal-organic frameworks for cancer immunotherapy

    Alsaiari, Shahad K.; Qutub, Somayah S.; Sun, Shichao; Baslyman, Walaa; Aldehaiman, Mansour M.; Alyami, Mram Z.; Almalik, Abdulaziz; Halwani, Rabih; Merzaban, Jasmeen; Mao, Zhengwei; Alsaiari, Shahad K. (Science Advances, American Association for the Advancement of Science (AAAS), 2021-01-22) [Article]
    The major impediments to the implementation of cancer immunotherapies are the sustained immune effect and the targeted delivery of these therapeutics, as they have life-threatening adverse effects. In this work, biomimetic metal-organic frameworks [zeolitic imidazolate frameworks (ZIFs)] are used for the controlled delivery of nivolumab (NV), a monoclonal antibody checkpoint inhibitor that was U.S. Food and Drug Administration–approved back in 2014. The sustained release behavior of NV-ZIF has shown a higher efficacy than the naked NV to activate T cells in hematological malignancies. The system was further modified by coating NV-ZIF with cancer cell membrane to enable tumor-specific targeted delivery while treating solid tumors. We envisage that such a biocompatible and biodegradable immunotherapeutic delivery system may promote the development and the translation of hybrid superstructures into smart and personalized delivery platforms.
  • Multiscale Assembly of [AgS 4 ] Tetrahedrons into Hierarchical Ag–S Networks for Robust Photonic Water

    Wu, Zhennan; Yao, Qiaofeng; Liu, Zhihe; Xu, Hongyi; Guo, Peng; Liu, Lingmei; Han, Yu; Zhang, Kuo; Lu, Zhongyuan; Li, Xuke; Zhang, Jiangwei; Xie, Jianping (Advanced Materials, Wiley, 2021-01-21) [Article]
    There is an urgent need to assemble ultrasmall metal chalcogenides (with atomic precision) into functional materials with the required anisotropy and uniformity, on a micro- or even macroscale. Here, a delicate yet simple chemistry is developed to produce a silver-sulfur network microplate with a high monodispersity in size and morphology. Spanning from the atomic, molecular, to nanometer, to micrometer scale, the key structural evolution of the obtained microplates includes 2D confinement growth, edge-sharing growth mode, and thermodynamically driven layer-by-layer stacking, all of which are derived from the [AgS<sub>4</sub> ] tetrahedron unit. The key to such a high hierarchical, complex, and accurate assembly is the dense deprotonated ligand layer on the surface of the microplates, forming an infinite surface with high negative charge density. This feature operates at an orderly distance to allow further hierarchical self-assembly on the microscale to generate columnar assemblies composed of microplate components, thereby endowing the feature of the 1D photonic reflector to water (i.e., photonic water). The reflective color of the resulting photonic water is highly dependent on the thickness of the building blocks (i.e., silver-sulfur microplates), and the coexistent order and fluidity help to form robust photonic water.
  • Artificial channels for confined mass transport at the sub-nanometre scale

    Shen, Jie; Liu, Gongping; Han, Yu; Jin, Wanqin (Nature Reviews Materials, Springer Science and Business Media LLC, 2021-01-21) [Article]
    Mass transport at the sub-nanometre scale, including selective transport of gases, liquids and ions, plays a key role in systems such as catalysis, energy generation and storage, chemical sensing and molecular separation. Highly efficient biological channels in living organisms have inspired the design of artificial channels with similar, or even higher, mass-transport efficiency, which can be used at a much larger scale. In this Review, we highlight synthetic-nanomaterials-enabled channels in the platforms of well-defined nanopores, 1D nanotubes and 2D nanochannels, and discuss their design principles, channel architectures and membrane or device fabrication. We focus on fundamental mechanisms of sub-nanometre confined mass transport and their relationships with the structure–property–performance. We then present the practicalities of these channels and discuss their potential impact on the development of next-generation sustainable technologies for use in applications related to energy, the environment and healthcare.
  • Electrolyte-Mediated Stabilization of High-Capacity Micro-Sized Antimony Anodes for Potassium-Ion Batteries

    Zhou, Lin; Cao, Zhen; Zhang, Jiao; Cheng, Hraoran; Liu, Gang; Park, Geon-Tae; Cavallo, Luigi; Wang, Limin; Alshareef, Husam N.; Sun, Yang-Kook; Ming, Jun (Advanced Materials, Wiley, 2021-01-20) [Article]
    Alloying anodes exhibit very high capacity when used in potassium-ion batteries, but their severe capacity fading hinders their practical applications. The failure mechanism has traditionally been attributed to the large volumetric change and/or their fragile solid electrolyte interphase. Herein, it is reported that an antimony (Sb) alloying anode, even in bulk form, can be stabilized readily by electrolyte engineering. The Sb anode delivers an extremely high capacity of 628 and 305 mAh g<sup>-1</sup> at current densities of 100 and 3000 mA g<sup>-1</sup> , respectively, and remains stable for more than 200 cycles. Interestingly, there is no need to do nanostructural engineering and/or carbon modification to achieve this excellent performance. It is shown that the change in K<sup>+</sup> solvation structure, which is tuned by electrolyte composition (i.e., anion, solvent, and concentration), is the main reason for achieving this excellent performance. Moreover, an interfacial model based on the K<sup>+</sup> -solvent-anion complex behavior is presented. The electronegativity of the K<sup>+</sup> -solvent-anion complex, which can be tuned by changing the solvent type and anion species, is used to predict and control electrode stability. The results shed new light on the failure mechanism of alloying anodes, and provide a new guideline for electrolyte design that stabilizes metal-ion batteries using alloying anodes.

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