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C58H42CdN10O6, triclinic, P1‾$P\overline{1}$ (no. 2), a = 9.689(3) Å, b = 10.930(3) Å, c = 23.321(6) Å, α = 80.838(5)°, β = 84.261(5)°, γ = 79.189(5)°, V = 2388.7(12) Å3, Z = 2, Rgt(F) = 0.0592, wRref(F2) = 0.1561, T = 293 K.

Two-dimensional (2D) semiconductors have attracted great attention to extend Moore’s law, which motivates the quest for fast growth of high-quality materials. However, taking MoS2 as an example, current methods yield 2D MoS2 with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial semiconductors. Here, we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS2. The grown MoS2 has the lowest density of sulfur vacancies (~1.41×1012 cm−2) reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm2 V−1 s−1. Theoretical calculations show that by incorporating iodine, the nucleation barrier of MoS2 growth with sulfur-terminated edges reduces dramatically. The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS2 domains within seconds. This work provides an effective method for the ultrafast growth of 2D semiconductors with high quality, which will promote their applications.

Preparing high‐quality 2D semiconductors represented by transition metal dichalcogenides (TMDCs) is of great importance for the next‐generation devices. However, currently available 2D TMDCs contain many atomic defects, which greatly affect their electronic and optical properties. This review starts with the formation of atomic defects and their effects on the properties of 2D TMDCs. Then, techniques for characterizing atomic defects are systematically summarized, including atomic‐resolution imaging and spectroscopy measurements. Further, recent progress on defect suppression during growth and defect repair after growth is reviewed. Finally, challenges and opportunities in this important field are discussed. [ABSTRACT FROM AUTHOR]

2D magnetic materials with distinct mechanical properties are of great importance for flexible spintronics. However, synthesizing 2D magnets with atomic thickness is challenging and their mechanical properties remain largely unexplored. Here, the growth of a ferrimagnetic 2D Cr9Se13 with anomalous elasticity is reported by an aged‐precursor‐assisted method. The obtained 2D Cr9Se13 exhibits an out‐of‐plane ferrimagnetic order with a coercivity larger than those of conventional magnetic materials. Noteworthy, it presents decent breaking strength and a Young's modulus of 52 ± 8 GPa that is among the smallest of the 2D family. This exceptional elasticity is attributed to the unique internal voids in Cr9Se13, as evidenced by the formed edge dislocations under strain. This work not only offers a facile method to synthesize 2D magnets but also develops avenues for obtaining 2D materials with desired mechanical properties, paving the way for future flexible spintronics. [ABSTRACT FROM AUTHOR]

C58H42CdN10O6, triclinic, P 1 ‾ (no. 2), a = 9.689(3) Å, b = 10.930(3) Å, c = 23.321(6) Å, α = 80.838(5)°, β = 84.261(5)°, γ = 79.189(5)°, V = 2388.7(12) Å3, Z = 2, Rgt(F) = 0.0592, wRref(F2) = 0.1561, T = 293 K. [ABSTRACT FROM AUTHOR]

Herein, an ultrasensitive DNAzyme-based fluorescence biosensor for detecting Cu2+ was designed using the cascade signal amplification strategy, coupling λ-exonuclease-assisted target recycling and mismatched catalytic hairpin assembly (MCHA). In the designed detection system, the target, Cu2+, can activate the Cu2+-dependent DNAzyme to cause a cleavage reaction, releasing ssDNA (tDNA). Then, tDNA binds to hairpin DNA (H0) with an overhanging 5′-phosphorylated terminus to form dsDNA with a blunt 5′-phosphorylated terminus, which activates the dsDNA to be digested by λ-Exo and releases tDNA along with another ssDNA (iDNA). Subsequently, the iDNA initiates MCHA, which can restore the fluorescence of carboxyfluorescein (FAM) previously quenched by tetramethylrhodamine (TAMRA), resulting in a strong fluorescent signal. Furthermore, MCHA efficiently improves the signal-to-noise ratio of the detection system. More importantly, tDNA recycling can be achieved with the λ-Exo digestion reaction to release more iDNA, efficiently amplifying the fluorescent signal and further improving the sensitivity to Cu2+ with a detection limit of 60 fM. The practical application of the developed biosensor was also demonstrated by detecting Cu2+ in real samples, proving it to be an excellent analytical strategy for the ultrasensitive quantification of heavy metal ions in environmental water sources. [ABSTRACT FROM AUTHOR]

Transition metal compounds are considered as competitive candidates for efficient noble-metal-free electrocatalysts in overall water splitting. However, a single material generally fails to maintain simultaneous activities in both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we developed a hybrid electrocatalyst of a Fe-(NiS2/MoS2)/carbon nanotube (CNT) film by combining composite and doping strategies, followed by a microstructure design of laser-drilled micropores, for high-efficiency overall water splitting and pH-universal HER. The charge transfer between MoS2 and NiS2 synergistically enhances both the HER and OER, and the light Fe doping further promotes the synergistic effect. The microstructure with periodic pores favors the release of bubbles, ensuring long-term stabilities at both low and large current densities without activity degradation. Consequently, Fe-(NiS2/MoS2)/CNT exhibits an ideal voltage, even lower than that of noble-metal electrodes, of 1.51 V at 10 mA cm−2 for overall water splitting in 1 M KOH, with η10 of the HER/OER at 87/234 mV, respectively. As a cathode, it also delivers low η10 values of 98 mV in 0.5 M H2SO4 and 127 mV in 1 M PBS, showing a pH-universal HER activity. Our work provides a comprehensive strategy towards high-efficiency electrocatalysts for overall water splitting, which will find a broad range of green energy applications. [ABSTRACT FROM AUTHOR]

Molybdenum dioxide (MoO2) and molybdenum disulfide (MoS2) are considered as promising non-precious metal electrocatalysts for the hydrogen evolution reaction (HER). However, the thermodynamic inactivity of MoO2 and poor conductivity of MoS2 result in unsatisfactory catalytic activities for individual materials. Here we developed a high-performance HER hetero-electrocatalyst of high-valence-cation doped MoS2/MoO2 composites incorporated in carbon nanotube (CNT) foam by a simple one-step synthesis. MoO2 is stably attached and partially sulfurized into MoS2 on CNT foam, which couples the features of abundant active sites of MoS2, good conductivity of MoO2, flexibility and porosity of the CNT foam matrix, and unique doping effects of high-valence cations to synergistically enhance the HER activity. This delicately designed hetero-electrocatalyst thus exhibits low overpotential (62 mV @ η10), small Tafel slope (44 mV dec−1), and extremely high double-layer capacitance (217.9 mF cm−2). The performance remains almost unchanged after hundreds/thousands of times of bending/CV scans, and shows long-term stability at both low and high currents. Experiments and density functional theory calculations suggest that the high-valence-cation doping improves both electrical conductivity and catalytic activity of the materials. This state-of-the-art electrocatalyst can be directly used as an easily processable, flexible, free-standing, and cost-effective electrode without binders in diverse environments. [ABSTRACT FROM AUTHOR]

Preparation of high-quality two-dimensional (2D) transition metal dichalcogenides (TMDCs) is the precondition for realizing their applications. However, the synthesized 2D TMDCs (e.g., MoS 2 ) crystals suffer from low quality due to the massive defects formed during the growth. Here, we report single-atom sulfur (S 1 ) as a highly reactive sulfur species to grow ultrahigh-quality monolayer MoS 2 . Derived from battery waste, sulfurized polyacrylonitrile (SPAN) is found to be exclusive and efficient in releasing S 1 . The monolayer MoS 2 prepared by SPAN exhibits an ultralow defect density of ∼7 × 10 12 cm -2 and the narrowest photoluminescence (PL) emission peak with full-width at half-maximum of ∼47.11 meV at room temperature. Moreover, the statistical resonance Raman and low-temperature PL results further verify the significantly lower defect density and higher optical quality of SPAN-grown MoS 2 than those of the conventional S-powder-grown samples. This work provides an effective approach for preparing ultrahigh-quality 2D single crystals, facilitating their industrial applications.

2D magnets have generated much attention due to their potential for spintronic devices. Heterostructures of 2D magnets are interesting platforms for exploring physical phenomena and applications. However, the controlled growth of 2D room-temperature ferromagnetic heterostructures is challenging. Here, one-pot chemical vapor deposition growth of stable 2D Cr 2 O 3 -CrN mosaic heterostructures (MHs) is reported with a controlled ratio of components that possess robust room-temperature ferromagnetism. The 2D MHs consist of Cr 2 O 3 flakes with embedded CrN subdomains and the CrN:Cr 2 O 3 ratio can be tuned from 0% to 100% during growth. By changing the CrN:Cr 2 O 3 ratio, the ferromagnetism of the MHs (e.g., saturation magnetization, coercive field), which originates from the interfacial coupling between Cr 2 O 3 and CrN, can be controlled. Importantly, the obtained Cr 2 O 3 -CrN MHs are stable in air at elevated temperatures and have robust ferromagnetism with Curie temperature >400 K. This work presents a facile method for fabricating 2D MHs with tunable magnetism which will benefit high-temperature spintronics., (© 2023 Wiley-VCH GmbH.)

Objective: To establish a two-dimensional gel electrophoresis (2-DE) map for comparative proteomic analysis of rat spinal cord with chronic morphine tolerance, and to detect differentially expression proteins that are associated with chronic morphine tolerance.
 Methods: Sixteen male SD rats received the intrathecal catheterization operation and they were randomly divided into a morphine tolerance group (MT group, n=8) and a saline group (NS group, n=8). The lumbar enlargement segments of the MT group and the NS group spinal cord were harvested and proteins were separated by 2-DE. Differential proteome profiles were established and analyzed by means of immobilized pH gradient-based two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The 2-DE maps were visualized after coomassie blue staining and analyzed using PDQuest analysis software. Identification of differential protein spots was conducted by MALDI-TOF-MS, and the Mascot query software was used to search Swiss-Prot database for bioinformatics analysis. Western blotting was used to verify the expression of some differentially expressed proteins.
 Results: A total of 1 000 spots were identified in 2-DE maps of rat spinal cord tissues from the MT group and the NS group, and 36 proteins were significantly differentially expressed in the MT group compared with the NS group. Identification was conducted by MALDI-TOF-MS and Swiss-Prot database through Mascot query software, and a total of 14 proteins were obtained. Among them, 2 protein spots were down-regulated in the MT group compared with that in the NS group, and 12 protein spots were up-regulated in the MT group compared with that in the NS group. Two kinds of proteins (NUDAA, ENOG) were verified by Western blotting and the results were consistent with proteomics data.
 Conclusion: The optimized 2-DE profiles for the proteome of spinal cord tissue in rats with chronic morphine tolerance is established preliminarily, which showed that morphine tolerance can cause changes in the expression of various proteins in the spinal cord.