Dendrite growth of alkali metal anodes limited their lifetime for charge/discharge cycling. Here, we report near-perfect anodes of lithium, sodium, and potassium metals achieved by electrochemical ...polishing, which removes microscopic defects and creates ultra-smooth ultra-thin solid-electrolyte interphase layers at metal surfaces for providing a homogeneous environment. Precise characterizations by AFM force probing with corroborative in-depth XPS profile analysis reveal that the ultra-smooth ultra-thin solid-electrolyte interphase can be designed to have alternating inorganic-rich and organic-rich/mixed multi-layered structure, which offers mechanical property of coupled rigidity and elasticity. The polished metal anodes exhibit significantly enhanced cycling stability, specifically the lithium anodes can cycle for over 200 times at a real current density of 2 mA cm
with 100% depth of discharge. Our work illustrates that an ultra-smooth ultra-thin solid-electrolyte interphase may be robust enough to suppress dendrite growth and thus serve as an initial layer for further improved protection of alkali metal anodes.
Based on the newly designed ligand 4′‐(3,5‐dicarboxyphenyl)‐4,2′:6′,4′′‐terpyridine (DCTP), a unique semi‐conductive 3D framework {CuΙCuΙΙ2(DCTP)2NO3⋅1.5 DMF}n (1) with a narrow band gap of 2.1 eV, ...was obtained and structurally characterized. DFT calculations with van de Waals correction employed to explore the electronic structure of 1, clearly revealed its semi‐conductive behavior. Furthermore, we found that 1 exhibits a superior band alignment with water to produce hydrogen and degrade organic pollutants. Without adding any photosensitizers, 1 displays an efficiently photocatalytic hydrogen production in water based on the photo‐generated electrons under UV/Vis light. 1 also exhibits excellent photo‐degradation of methyl blue under visible‐light owing to the strong oxidization of excited holes. It is the first example of MOFs with doubly photocatalytic activities related to photo‐generated electrons and holes, respectively.
Narrow band gap: The metal–organic framework (MOF) {CuΙCuΙΙ2(DCTP)2NO3⋅1.5 DMF}n has a narrow band gap of 2.1 eV and is a semiconductor. Theoretical and experimental investigations confirmed its performance in photocatalytic hydrogen generation and in organic‐dye degradation. It is the first report for MOFs exhibiting two different photocatalytic activities based on photo‐generated electrons and holes.
Lithium metal anodes suffer from poor cycling stability and potential safety hazards. To alleviate these problems, Li thin‐film anodes prepared on current collectors (CCs) and Li‐free types of anodes ...that involve direct Li plating on CCs have received increasing attention. In this study, the atomic‐scale design of Cu‐CC surface lithiophilicity based on surface lattice matching of the bcc Li(110) and fcc Cu(100) faces as well as electrochemical achievement of Cu(100)‐preferred surfaces for smooth Li deposition with a low nucleation barrier is reported. Additionally, a purposely designed solid–electrolyte interphase is created for Li anodes prepared on CCs. Not only is a smooth planar Li thin film prepared, but a uniform Li plating/stripping on the skeleton of 3D CCs is achieved as well by high utilization of the surface and cavities of the 3D CCs. This work demonstrates surface electrochemistry approaches to construct stable Li metal–electrolyte interphases towards practical applications of Li anodes prepared on CCs.
Get in touch with lithium: The generation of surface lithiophilicity on planar and 3D Cu hosts for Li metal anodes is reported. Enabled by a lattice matching of Cu(100) and Li(110), smooth deposition of Li thin films and the creation of ultra‐smooth ultra‐thin SEI on the Cu hosts is made possible. This allows a high utilization of not only the surface but also cavities of the Cu hosts.
The development of high-performance near-infrared organic light-emitting diodes is hindered by strong non-radiative processes as governed by the energy gap law. Here, we show that exciton ...delocalization, which serves to decouple the exciton band from highly vibrational ladders in the S0 ground state, can bring substantial enhancements in the photoluminescence quantum yield of emitters, bypassing the energy gap law. Experimental proof is provided by the design and synthesis of a series of new Pt(ii) complexes with a delocalization length of 5–9 molecules that emit at 866–960 nm with a photoluminescence quantum yield of 5–12% in solid films. The corresponding near-infrared organic light-emitting diodes emit light with a 930 nm peak wavelength and a high external quantum efficiency up to 2.14% and a radiance of 41.6 W sr−1 m−2. Both theoretical and experimental results confirm the exciton–vibration decoupling strategy, which should be broadly applicable to other well-aligned molecular solids.Pt(ii) complexes allow the fabrication of efficient near-infrared organic light-emitting diodes that operate beyond the 900 nm region.
For many regenerative electrochemical energy‐conversion systems, hybrid electrocatalysts comprising transition metal (TM) oxides and heteroatom‐doped (e.g., nitrogen‐doped) carbonaceous materials are ...promising bifunctional oxygen reduction reaction/oxygen evolution reaction electrocatalysts, whose enhanced electrocatalytic activities are attributed to the synergistic effect originated from the TM–N–C active sites. However, it is still ambiguous which configuration of nitrogen dopants, either pyridinic or pyrrolic N, when bonded to the TM in oxides, predominately contributes to the synergistic effect. Herein, an innovative strategy based on laser irradiation is described to controllably tune the relative concentrations of pyridinic and pyrrolic nitrogen dopants in the hybrid catalyst, i.e., NiCo2O4 NPs/N‐doped mesoporous graphene. Comparative studies reveal the dominant role of pyridinic‐NCo bonding, instead of pyrrolic‐N bonding, in synergistically promoting reversible oxygen electrocatalysis. Moreover, density functional theory calculations provide deep insights into the corresponding synergistic mechanism. The optimized hybrid, NiCo/NLG‐270, manifests outstanding reversible oxygen electrocatalytic activities, leading to an overpotential different ΔE among the lowest value for highly efficient bifunctional catalysts. In a practical reversible Zn–air battery, NiCo/NLG‐270 exhibits superior charge/discharge performance and long‐term durability compared to the noble metal electrocatalysts.
An innovative strategy based on laser irradiation is developed to selectively regulate relative contents of pyridinic and pyrrolic nitrogen in NiCo2O4/N‐graphene hybrids. Strong chemical bonding forms between nitrogen and cobalt, and pyridinic‐NCo bonds, instead of pyrrolic‐NCo bonds, are identified to predominantly contribute to synergistic catalysis, leading to substantially enhanced oxygen electrocatalytic activities, outperforming a combination of benchmark noble metal catalysts.
Intelligent reflecting surface (IRS) offers a cost-effective solution to link blockage problem in mmWave communications, and the prerequisite of which is the accurate estimation of (1) the optimal ...beams for base station/access point (BS/AP) and mobile terminal (MT), (2) the optimal reflection patterns for IRSs, and (3) link blockage. In this paper, we carry out beam training designs for IRSs assisted mmWave communications to estimate the aforementioned parameters. To acquire the optimal beams and reflection patterns, we firstly perform random beamforming and maximum likelihood estimation to estimate angle of arrival (AoA) and angle of departure (AoD) of the line of sight (LoS) path between BS/AP (or IRSs) and MT. Then, with the estimated AoDs, we propose an iterative positioning algorithm that achieves centimeter-level positioning accuracy. The obtained location information is not only a fringe benefit but also enables us to cross verify and enhance the estimation of AoA and AoD, and it also facilitates the estimation of blockage indicator. Numerical results show the superiority of our proposed beam training scheme and verify the performance gain brought by location information.
Abstract
As the water-gas shift (WGS) reaction serves as a crucial industrial process, strategies for developing robust WGS catalysts are highly desiderated. Here we report the construction of ...stabilized bulk-nano interfaces to fabricate highly efficient copper-ceria catalyst for the WGS reaction. With an in-situ structural transformation, small CeO
2
nanoparticles (2–3 nm) are stabilized on bulk Cu to form abundant CeO
2
-Cu interfaces, which maintain well-dispersed under reaction conditions. This inverse CeO
2
/Cu catalyst shows excellent WGS performances, of which the activity is 5 times higher than other reported Cu catalysts. Long-term stability is also very solid under harsh conditions. Mechanistic study illustrates that for the inverse CeO
2
/Cu catalyst, superb capability of H
2
O dissociation and CO oxidation facilitates WGS process via the combination of associative and redox mechanisms. This work paves a way to fabricate robust catalysts by combining the advantages of bulk and nano-sized catalysts. Catalysts with such inverse configurations show great potential in practical WGS applications.
For high-temperature catalytic reaction, it is of significant importance and challenge to construct stable active sites in catalysts. Herein, we report the construction of sufficient and stable ...copper clusters in the copper‒ceria catalyst with high Cu loading (15 wt.%) for the high-temperature reverse water gas shift (RWGS) reaction. Under very harsh working conditions, the ceria nanorods suffered a partial sintering, on which the 2D and 3D copper clusters were formed. This partially sintered catalyst exhibits unmatched activity and excellent durability at high temperature. The interaction between the copper and ceria ensures the copper clusters stably anchored on the surface of ceria. Abundant in situ generated and consumed surface oxygen vacancies form synergistic effect with adjacent copper clusters to promote the reaction process. This work investigates the structure-function relation of the catalyst with sintered and inhomogeneous structure and explores the potential application of the sintered catalyst in C1 chemistry.
Lithium‐sulfur (Li‐S) batteries have attracted tremendous interest because of their high theoretical energy density and cost effectiveness. The target of Li‐S battery research is to produce batteries ...with a high useful energy density that at least outperforms state‐of‐the‐art lithium‐ion batteries. However, due to an intrinsic gap between fundamental research and practical applications, the outstanding electrochemical results obtained in most Li‐S battery studies indeed correspond to low useful energy densities and are not really suitable for practical requirements. The Li‐S battery is a complex device and its useful energy density is determined by a number of design parameters, most of which are often ignored, leading to the failure to meet commercial requirements. The purpose of this review is to discuss how to pave the way for reliable Li‐S batteries. First, the current research status of Li‐S batteries is briefly reviewed based on statistical information obtained from literature. This includes an analysis of how the various parameters influence the useful energy density and a summary of existing problems in the current Li‐S battery research. Possible solutions and some concerns regarding the construction of reliable Li‐S batteries are comprehensively discussed. Finally, insights are offered on the future directions and prospects in Li‐S battery field.
The research status of Li‐S batteries is briefly reviewed based on statistical analysis results. A summary of existing problems in the current Li‐S battery research is concluded with possible solutions and some concerns comprehensively discussed. Perspectives are proposed with respect to more reliable lithium‐sulfur batteries with rationally improved performance.
Nucleotide-binding, leucine-rich repeat receptors (NLRs) perceive pathogen effectors to trigger plant immunity. Biochemical mechanisms underlying plant NLR activation have until now remained poorly ...understood. We reconstituted an active complex containing the
coiled-coil NLR ZAR1, the pseudokinase RKS1, uridylated protein kinase PBL2, and 2'-deoxyadenosine 5'-triphosphate (dATP), demonstrating the oligomerization of the complex during immune activation. The cryo-electron microscopy structure reveals a wheel-like pentameric ZAR1 resistosome. Besides the nucleotide-binding domain, the coiled-coil domain of ZAR1 also contributes to resistosome pentamerization by forming an α-helical barrel that interacts with the leucine-rich repeat and winged-helix domains. Structural remodeling and fold switching during activation release the very N-terminal amphipathic α helix of ZAR1 to form a funnel-shaped structure that is required for the plasma membrane association, cell death triggering, and disease resistance, offering clues to the biochemical function of a plant resistosome.
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