It is still of great difficulty to develop the non‐platinum catalyst with high catalytic efficiency towards hydrogen evolution reaction via the strategies till now. Therefore, it is necessary to ...develop the new methods of catalyst designing. Here, we put forward the catalyst designed by the electronic metal–support interaction (EMSI), which is demonstrated to be a reliable strategy to find out the high‐efficiency catalyst. We carried out the density functional theory calculation first to design the proper EMSI of the catalyst. We applied the model of M1‐M2‐X (X=C, N, O) during the calculation. Among the catalysts we chose, the EMSI of Rh1TiC, with the active sites of Rh1‐Ti2C2, is found to be the most proper one for HER. The electrochemical experiment further demonstrated the feasibility of the EMSI strategy. The single atomic site catalyst of Rh1‐TiC exhibits higher catalytic efficiency than that of state‐of‐art Pt/C. It achieves a small overpotential of 22 mV and 86 mV at the at the current density of 10 mA cm−2 and 100 mA cm−2 in acid media, with a Tafel slope of 25 mV dec−1 and a mass activity of 54403.9 mA cm−2 mgRh−1 (vs. 192.2 mA cm−2 mgPt−1 of Pt/C). Besides, it also shows appealing advantage in energy saving compared with Pt/C (≈20 % electricity consuming decrease at 2 kA m−2) Therefore, we believe that the strategy of regulating EMSI can act as a possible way for achieving the high catalytic efficiency on the next step of SACs.
The electronic metal–support interaction (EMSI) is closely related to the electronic structure of active sites, which determines the catalytic activity. We put forward a method of designing the EMSI of single‐atomic site catalysts (SACs) to achieve high efficiency. The SACs achieve a lower overpotential and higher mass activity than any other SACs towards hydrogen evolution reaction, demonstrating the benefits of this method.
Semitransparent organic photovoltaics (ST‐OPVs) have great potential for use in renewable energy technologies. In bulk‐heterojunction (BHJ) ST‐OPVs, a compromise is necessary between the visible ...light transmittance (VLT) and the power conversion efficiency (PCE). A sequential deposition (SD) strategy that involves individually depositing a polymer donor layer (D) and a small‐molecule acceptor layer (A) as the active layer is presented; where molecular diffusion occurring at the interfacial region results in a pseudo p–i–n structure. PBDB‐T‐2F(D)/Y6(A) ST‐OPVs are fabricated with different active layer thicknesses—at 115 nm, the SD (D:A/75:40 nm) and BHJ devices (D:A/1:1.2 w) provide the champion PCE of 12.91% (VLT of 14.5%) and 12.77% (VLT of 13.4%), respectively; at 85 nm, the SD (D:A/45:40 nm) and BHJ devices (D:A/1:1.2 w) provide a PCE of 12.22% (VLT of 22.2%) and 11.23% (VLT of 16.6%), respectively. This trend indicates SD devices have larger PCE and VLT values than the BHJ devices at a given active layer thickness, and the enhancements of PCE and VLT values by the SD structures against the BHJ structures become more pronounced as the active layer thickness reduced. The SD strategy provides a new approach for achieving ST‐OPVs with both high efficiency and high transparency.
In typical semitransparent organic photovoltaics (ST‐OPVs) that incorporate bulk heterojunction (BHJ) active layers, a compromise is made between the visible light transmittance (VLT) and power conversion efficiency (PCE). A new strategy with a sequential‐deposition (SD) active layer involving pseudo p–i–n structures provides ST‐OPVs with simultaneously higher PCE and VLT than that of the BHJ devices at the same layer thickness.
Palladium diselenide (PdSe2), a peculiar noble metal dichalcogenide, has emerged as a new two-dimensional material with high predicted carrier mobility and a widely tunable band gap for device ...applications. The inherent in-plane anisotropy endowed by the pentagonal structure further renders PdSe2 promising for novel electronic, photonic, and thermoelectric applications. However, the direct synthesis of few-layer PdSe2 is still challenging and rarely reported. Here, we demonstrate that few-layer, single-crystal PdSe2 flakes can be synthesized at a relatively low growth temperature (300 °C) on sapphire substrates using low-pressure chemical vapor deposition (CVD). The well-defined rectangular domain shape and precisely determined layer number of the CVD-grown PdSe2 enable us to investigate their layer-dependent and in-plane anisotropic properties. The experimentally determined layer-dependent band gap shrinkage combined with first-principle calculations suggest that the interlayer interaction is weaker in few-layer PdSe2 in comparison with that in bulk crystals. Field-effect transistors based on the CVD-grown PdSe2 also show performances comparable to those based on exfoliated samples. The low-temperature synthesis method reported here provides a feasible approach to fabricate high-quality few-layer PdSe2 for device applications.
Ligands are the most commonly used means to control the regioselectivity of organic reactions. It is very important to develop new regioselective control methods for organic synthesis. In this study, ...we designed and synthesized a single-atomic-site catalyst (SAC), namely, Cu1-TiC, with strong electronic metal–support interaction (EMSI) effects by studying various reaction mechanisms. π cloud back-donation to the alkyne on the metal catalytic intermediate was enhanced during the reaction by using transient electron-rich characteristics. In this way, the reaction achieved highly linear-E-type regioselective conversion of electronically unbiased alkynes and completely avoided the formation of branched isomers (ln:br >100:1, TON up to 612, 3 times higher than previously recorded). The structural elements of the SACs were designed following the requirements of the synthesis mechanism. Every element in the catalyst played an important role in the synthesis mechanism. This demonstrated that the EMSI, which is normally thought to be responsible for the improvement in catalytic efficiency and durability in heterogeneous catalysis, now first shows exciting potential for regulating the regioselectivity in homogeneous catalysis.
Incorporation of N,S‐codoped nanotube‐like carbon (N,S‐NTC) can endow electrode materials with superior electrochemical properties owing to the unique nanoarchitecture and improved kinetics. Herein, ...α‐MnS nanoparticles (NPs) are in situ encapsulated into N,S‐NTC, preparing an advanced anode material (α‐MnS@N,S‐NTC) for lithium‐ion/sodium‐ion batteries (LIBs/SIBs). It is for the first time revealed that electrochemical α → β phase transition of MnS NPs during the 1st cycle effectively promotes Li‐storage properties, which is deduced by the studies of ex situ X‐ray diffraction/high‐resolution transmission electron microscopy and electrode kinetics. As a result, the optimized α‐MnS@N,S‐NTC electrode delivers a high Li‐storage capacity (1415 mA h g−1 at 50 mA g−1), excellent rate capability (430 mA h g−1 at 10 A g−1), and long‐term cycling stability (no obvious capacity decay over 5000 cycles at 1 A g−1) with retained morphology. In addition, the N,S‐NTC‐based encapsulation plays the key roles on enhancing the electrochemical properties due to its high conductivity and unique 1D nanoarchitecture with excellent protective effects to active MnS NPs. Furthermore, α‐MnS@N,S‐NTC also delivers high Na‐storage capacity (536 mA h g−1 at 50 mA g−1) without the occurrence of such α → β phase transition and excellent full‐cell performances as coupling with commercial LiFePO4 and LiNi0.6Co0.2Mn0.2O2 cathodes in LIBs as well as Na3V2(PO4)2O2F cathode in SIBs.
α‐MnS nanoparticles are in situ encapsulated into N,S‐codoped nanotube‐like carbon (α‐MnS@N,S‐NTC) as an advanced anode for Li/Na‐ion batteries. The α → β phase transition during the 1st cycle in LIBs is for the first time revealed by ex situ X‐ray diffraction and high‐resolution transmission electron microscopy studies, which improves the electrode kinetics and Li‐storage properties. α‐MnS@N,S‐NTC also exhibits superior performance in Li/Na‐ion half/full cells.
A nanolaser is a key component for on-chip optical communications and computing systems. Here, we report on the low-threshold, continuous-wave operation of a subdiffraction nanolaser based on surface ...plasmon amplification by stimulated emission of radiation. The plasmonic nanocavity is formed between an atomically smooth epitaxial silver film and a single optically pumped nanorod consisting of an epitaxial gallium nitride shell and an indium gallium nitride core acting as gain medium. The atomic smoothness of the metallic film is crucial for reducing the modal volume and plasmonic losses. Bimodal lasing with similar pumping thresholds was experimentally observed, and polarization properties of the two modes were used to unambiguously identify them with theoretically predicted modes. The all-epitaxial approach opens a scalable platform for low-loss, active nanoplasmonics.
Abstract
Intrinsic antiferromagnetism in van der Waals (vdW) monolayer (ML) crystals enriches our understanding of two-dimensional (2D) magnetic orders and presents several advantages over ...ferromagnetism in spintronic applications. However, studies of 2D intrinsic antiferromagnetism are sparse, owing to the lack of net magnetisation. Here, by combining spin-polarised scanning tunnelling microscopy and first-principles calculations, we investigate the magnetism of vdW ML CrTe
2
, which has been successfully grown through molecular-beam epitaxy. We observe a stable antiferromagnetic (AFM) order at the atomic scale in the ML crystal, whose bulk is ferromagnetic, and correlate its imaged zigzag spin texture with the atomic lattice structure. The AFM order exhibits an intriguing noncollinear spin reorientation under magnetic fields, consistent with its calculated moderate magnetic anisotropy. The findings of this study demonstrate the intricacy of 2D vdW magnetic materials and pave the way for their in-depth analysis.
Current efforts in the proteolysis targeting chimera (PROTAC) field mostly focus on choosing an appropriate E3 ligase for the target protein, improving the binding affinities towards the target ...protein and the E3 ligase, and optimizing the PROTAC linker. However, due to the large molecular weights of PROTACs, their cellular uptake remains an issue. Through comparing how different warhead chemistry, reversible noncovalent (RNC), reversible covalent (RC), and irreversible covalent (IRC) binders, affects the degradation of Bruton's Tyrosine Kinase (BTK), we serendipitously discover that cyano-acrylamide-based reversible covalent chemistry can significantly enhance the intracellular accumulation and target engagement of PROTACs and develop RC-1 as a reversible covalent BTK PROTAC with a high target occupancy as its corresponding kinase inhibitor and effectiveness as a dual functional inhibitor and degrader, a different mechanism-of-action for PROTACs. Importantly, this reversible covalent strategy is generalizable to improve other PROTACs, opening a path to enhance PROTAC efficacy.
Chiral oxindoles are important chemical scaffolds found in many natural products, and their enantioselective synthesis thus attracts considerable attention. Highly diastereo‐ and enantioselective ...synthetic methods for constructing C3 quaternary oxindoles have been well‐developed. However, the efficient synthesis of chiral 3‐substituted tertiary oxindoles has been rarely reported due to the ease of racemization of the tertiary stereocenter via enolization. Therefore, we herein report on the multicomponent assembly (from N‐aryl diazoamides, aldehydes, and enamines/indoles) of complex oxindoles by enantioselective cooperative catalysis. These reactions proceed under mild conditions and show broad substrate scope, affording the desired coupling products (>90 examples) with good to excellent stereocontrol. Additionally, this research also demonstrates the synthetic potential of this annulation by constructing the 6,6,5‐tricyclic lactone core structure of Speradine A.
Ternary catalysis enabled the three‐component reaction of N‐aryl diazoamides, aldehydes, and enamines/indoles, providing access to polyfunctionalized oxindoles in good yields with excellent diastereoselectivities and enantioselectivities (>90 examples, up to 94 % yield, 99 % ee, and >20 : 1 dr). The reaction involves the assembly of two highly reactive intermediates generated in situ by orthogonal catalytic processes under mild and operationally simple reaction conditions.
A novel in situ chemical upcycling strategy for plastic waste is proposed by the customized diphenylacetylene monomer with dual photo‐response. That is, diphenylacetylene reactive monomers are in ...situ inserted into the macromolecular chain of polyethylene terephthalate (PET) plastics/fibers through one‐pot transesterification of slight‐depolymerization and re‐polymerization. On the one hand, the diphenylacetylene group absorbs short‐wave high‐energy UV rays and then releases long‐wave low‐energy harmless fluorescence. On the other hand, the UV‐induced photo‐crosslinking reaction among diphenylacetylene groups produces extended π‐conjugated structure, resulting in a red‐shift (due to decreased HOMO–LUMO separation) in the UV absorption band and locked crosslink points between PET chains. Therefore, with increasing UV exposure time, the upcycled PET plastics exhibit reverse enhanced UV resistance and mechanical strength (superior to original performance), instead of serious UV‐photodegradation and damaged performance. This upcycling strategy at oligomer‐scale not only provides a new idea for traditional plastic recycling, but also solves the common problem of gradual degradation of polymer performance during use.
Starting from the oligomer‐scale, this work implements a novel in situ chemical upcycling strategy for PET plastic wastes through tailored diphenylacetylene monomer. Uniquely, the dual photo‐responses of diphenylacetylene enable upcycled PET plastics with reverse enhanced UV‐resistance and strength.
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