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Single-element van der Waals material has triggered a booming exploration since its simple theoretical modeling and highly integration ability. Elemental tellurium (Te) has a narrow band gap, high environmental stability and superior photoelectronic properties, making it one of the strong candidate materials for advanced broadband photodetectors. Moreover, its asymmetrical chain structure and inherent anisotropic piezoelectricity lays the foundations for artificial modification by strain-engineering. In this study, the Te-based prototype photodetectors were demonstrated with a stable, strong photoresponse at λ = 10.8 µm at room temperature. The photoresponsivity and detectivity were 9.34 mA/W and 8.63 × 107 Jones and can be enhanced by mechanical bending strain. The convex strain of 0.33 % significantly suppresses the dark current of Te photodetector since the stretching of Te-Te bond increases the inherent electrical resistance, which in turn enhances its photoresponsivity to 1080 %. Besides, we observed the bending direction is closely related to the modulation mechanism. The concave bending greatly improved the effective light absorption by rolling up the flexible device in the direction of light radiation, which dominants the enhanced photocurrent and photoresponsivity reaches 60.03 mA/W. This work demonstrates a feasible approach for enhancing Te-based infrared photodetection through an appropriate mechanical stimulus, and should has immense potential for the flexible applications of piezoelectronics and optoelectronics. • The large area Te nanofilms were successfully grown by physical vapor deposition. • The photoresponsivity and detectivity of prototype Te photodetector are 9.34 mA/W and 8.63 × 107 Jones at 10.8 µm. • The directional bending strain effectively enhanced the photoresponsivity by 2800 % to 60.03 mA/W. • The bending direction would raise different modulation mechanisms and improvements on photodetection properties. [ABSTRACT FROM AUTHOR]

High-entropy oxides (HEOs) exhibit excellent structural stability, and the synergistic effects among their constituent elements contribute to performance enhancement, providing vast opportunities for designing novel and efficient electrocatalysts. Utilizing four common transition metals such as Fe, Co, Ni, and Cr as the base and introducing a fifth metal, M (M = Mg, Mn, Zn, and Cu), with different outer electron shells, relevant high-entropy oxides with varying sizes were successfully synthesized via the hydrothermal method. Among all considered samples, FCNCMg, with the smallest particle size, possessed a much larger specific surface area, leading to the exposure of more active sites and thus favoring an improvement of the OER performance. The introduction of the fifth metal induced a redistribution of charges among Fe, Co, Ni, and Cr within the catalyst, resulting in different oxidation states for these metals. Mg addition led the XPS peaks of Fe/Ni and Cr/Co elements to shift towards lower and higher binding energies, respectively. This dynamic compensation effect between metal ions synergistically promoted their OER performance. In alkaline environments, FCNCMg exhibited the best OER performance, with an overpotential of 278 mV at 10 mA cm−2 and a Tafel slope of 49.90 mV dec−1. Moreover, it demonstrated excellent stability, achieving 50 h at 10 mA cm−2 and 20 h at 50 mA cm−2. This study, by controlling the composition of HEOs, explored the impact of particle size and synergistic effects on their performance, offering new insights for design and optimization of relevant high-performance HEOs. • A series of spinel (Fe 0.2 Co 0.2 Ni 0.2 Cr 0.2 M 0.2) 3 O 4 materials were successfully synthesized. • The introduction of M (M = Mg, Mn, Zn, and Cu) leads to tunable oxidation states of other elements. • The dynamic compensation effect among metal ions promots the OER activity of the catalysts. • FCNCMg exhibits an overpotential of 278 mV at 10 mA cm−2 and a Tafel slope of 49.90 mV dec−1. • FCNCMg can sustain stably for 50 h at 10 mA cm−2 and 20 h at 50 mA cm−2. [ABSTRACT FROM AUTHOR]

• Branched Ni 3 C nanoparticles in situ grown on the reduced graphene oxide (rGO). • Ni 3 C/rGO composite exhibited a minimum reflection loss of − 42.8 dB. • More interfacial polarization active sites improved reflection loss. Carbide/carbon composites are new types of electromagnetic (EM) wave absorbing materials because of their good stability, light weight, easy synthesis and excellent performance. In this work, monodisperse branched nickel carbide (Ni 3 C) nanoparticles with controlled morphology were fabricated through high-temperature pyrolysis of nickel acetylacetonate under anhydrous and oxygen-free conditions. Then Ni 3 C nanoparticles were uniformly in situ grown on the surface of reduced graphene oxide (rGO) to form nickel carbide/reduced graphene oxide (Ni 3 C/rGO) nanocomposite. Series of characterization and performance tests were conducted, and the results showed that the EM wave absorption performance of Ni 3 C/rGO composite was greatly enhanced compared with that of pure phase Ni 3 C nanoparticles. Due to the combined effects of interfacial polarization loss, conductivity loss and surface defects, Ni 3 C/rGO nanocomposite exhibited strong reflection loss in 2–18 GHz band, which could attenuate the EM waves incident to the internal loss to a greater extent. When the Ni 3 C/rGO composite is at 3.5 mm thickness, the maximum effective absorption bandwidth can reach 3.6 GHz, and at 3.0 mm thickness, the lowest reflection loss value can reach − 42.8 dB. This high-performance nanocomposite can be a new candidate material for EM wave absorption. [ABSTRACT FROM AUTHOR]

By an in situ hot-injection synthetic method, an anode material composed of monodispersed Ni 12 P 5 nanocrystals in situ grown into three dimensional (3D) reduced graphene oxide (rGO) matrix has been manufactured. The process of fabrication includes functionalization of graphene oxide, nucleation, crystallization and ligand removal. Simple operation, relatively mild and scalable reaction conditions as well as three dimensional (3D) interconnected porous rGO as the matrix have been utilized in the process of fabrication. In the assembled nanostructure, the high electrical conductivity and the interconnected porous network of rGO have contributed to the Ni 12 P 5 /rGO nanocomposites with fast channels for lithium-ion transport and electron transfer. Besides, the Ni 12 P 5 nanocrystals have a small size and monodispersed phase, which are able to accommodate the volume expansion during cycling. Therefore, Ni 12 P 5 /rGO nanocomposites present excellent electrochemical lithium-storage performance, including long-life cycling stability, high heat resistance and high rate capability. [Display omitted] • The monodispersed Ni 12 P 5 nanocrystals grown in situ into reduced graphene oxide matrix via hot-injection method. • Ni 12 P 5 /rGO nanocomposites exhibit excellent lituium-storage performance with long cycle life, high thermal stability, and high rate capability. • The design includes the simple operation of the entire preparation process, mild reaction conditions, and a continuous, scalable production process. [ABSTRACT FROM AUTHOR]

Designing efficient, stable, and inexpensive catalysts for water splitting was critical for efficient, sustainable energy conversion. Here, a one-pot hot-colloidal route was adopted to synthesize the mono-dispersed NiCoP catalyst with a particle size of∼5.0 nm. To further improve the structural stability and electronic conductivity of the catalysts, carbon nanotubes (CNTs) were introduced. The theoretical calculations suggested that a synergistic effect between Ni and Co in the NiCoP catalyst not only leads to an obvious charge redistribution but also facilitates the electron transfer from the surface to the reactant intermediates, being responsible for the optimal ΔG H* of the catalyst. As a result, NiCoP/CNTs exhibited good HER performance both in acidic and alkaline electrolytes. The overpotentials under alkaline and acidic electrolytes were 110 mV and114 mV at a current density of 10 mA cm−2, respectively. In comparison with pristine Ni 2 P(Co 2 P), the overpotential of NiCoP/CNTs in acidic and alkaline electrolytes was reduced by 50(24) and 62(30) mV at the current density of 10 mA cm−2. Even at the current densities of 50 and 200 mA cm−2, NiCoP/CNTs still retains a much lower overpotential than other samples. Our results revealed the important roles of the synergistic effect between the transition metals and the interaction between CNTs and the phosphides, which provides some useful information for the design and optimization of relevant HER catalysts. • Synergistic interaction between Ni and Co in NiCoP/CNTs leads to charge redistribution favoring electron transfer. • CNTs can improve the conductivity of the material, reduce the interfacial impedance and increase specific surface area. • CNTs facilitate anchoring and uniform distribution of catalyst particles. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries appear to be one of the most promising energy-storage devices owing to the unparalleled theoretical specific energy, relatively inexpensive price and abundant resources. Despite these attractive features, the practical performances of sulfur cathode still remain a lot of challenges, such as the electrical insulating nature of S and Li 2 S, huge volume change during cycling, notorious shuttle effect of lithium polysulfide intermediates (LiPSs), sluggish redox kinetics and construction of thick electrodes with high sulfur loading. Here, CoFe 2 O 4 nanoparticles anchored on the carbon nanotube (CNT) paper is proposed as free-standing sulfur host to address the issues. The cross-linking CNT network can serve as conductive matrix and accommodate volume change upon cycling simultaneously. Meanwhile, the CoFe 2 O 4 nanoparticles are capable of effectively anchoring LiPSs to suppress the shuttle effect and accelerating LiPSs conversion to boost redox kinetics. Moreover, the free-standing paper electrode without any binder is conducive to constructing stable cathode with high sulfur loading. In consequence, the well-designed S/CoFe 2 O 4 /CNT paper cathodes deliver impressive electrochemical performance, demonstrating an initial discharge capacity of 755.3 mAh g−1 and remaining a high reversible capacity of 642.6 mAh g−1 after 400 cycles at 2 C with an inconspicuous decay of 0.04% per cycle. The bimetallic oxide CoFe 2 O 4 nanoparticles anchored on the carbon nanotube paper is proposed as free-standing sulfur host with enhanced polysulfide trapping and catalytic effects for advanced Li-S batteries. [Display omitted] • Binder-free host realizes high sulfur loading and energy density for Li-S battery. • CoFe 2 O 4 /CNT paper inhibits the polysulfide shuttling via strong chemical interaction. • CNT-anchored CoFe 2 O 4 catalytically promotes the polysulfide conversion kinetics. • The Li-S battery with S/CoFe 2 O 4 /CNT cathode exhibits enhanced capacity and stability. [ABSTRACT FROM AUTHOR]