Ag-modified enhance the performances of ZnO@CFs based omnidirectional photoelectrochemical ultraviolet detectors.

There are several prospective applications for omnidirectional ultraviolet (UV) detectors and underwater detection detectors in optical systems and optical fields. In this work, ZnO nanorods arrays were grown on carbon fibers (CFs). An appropriate amount of Ag nanoparticles (NPs) was deposited on the surface of ZnO nanorods by photochemical deposition. This improved the performance of photoelectrochemical (PEC) based UV detectors. Under 365 nm and 10 mW cm-2UV irradiation, the photocurrent density of the 30s-Ag/ZnO@CFs based PEC UV detector can reach 1.28 mA cm-2, which is about 7 times that of the ZnO@CFs based PEC UV detector, and the rising time is shortened from 0.17 to 0.10 s. The reason is that increased absorption of ultraviolet light induced by the localized surface plasmon resonance. In addition, the detector exhibits a good flexibility and remains flexible after hundreds of bends and twists. Moreover, the detector is responsive in the range of rotation angle from 0° to 360°. It provides an insight to improve the photoelectric performance and underwater omnidirectional detection ability of the PEC UV detector.

Boosting Charge Transport and Catalytic Performance in MoS2 by Zn2+ Intercalation Engineering for Lithium-Sulfur Batteries.

Transition metal dichalcogenides (TMDs) have been widely studied as catalysts for lithium-sulfur batteries due to their good catalytic properties. However, their poor electronic conductivity leads to slow sulfur reduction reactions. Herein, a simple Zn2+ intercalation strategy was proposed to promote the phase transition from semiconducting 2H-phase to metallic 1T-phase of MoS2. Furthermore, the Zn2+ between layers can expand the interlayer spacing of MoS2 and serve as a charge transfer bridge to promote longitudinal transport along the c-axis of electrons. DFT calculations further prove that Zn-MoS2 possesses better charge transfer ability and stronger adsorption capacity. At the same time, Zn-MoS2 exhibits excellent redox electrocatalytic performance for the conversion and decomposition of polysulfides. As expected, the lithium-sulfur battery using Zn0.12MoS2-carbon nanofibers (CNFs) as the cathode has high specific capacity (1325 mAh g-1 at 0.1 C), excellent rate performance (698 mAh g-1 at 3 C), and outstanding cycle performance (it remains 604 mAh g-1 after 700 cycles with a decay rate of 0.045% per cycle). This study provides valuable insights for improving electrocatalytic performance of lithium-sulfur batteries.

Construction of urchin-like bimetallic phosphides induced by carbon dots for efficient wide pH hydrogen production.

The development of an efficient noble-metal-free and pH-universal electrocatalyst for the hydrogen evolution reaction (HER) would be highly significant for hydrogen (H2) production via electrocatalytic water splitting. However, developing such a catalyst remains a formidable task. Herein, a strategy is proposed for the in situ fabrication of a novel urchin-like NiCoP microsphere catalyst (0.5CDs-NiCoP/NF) on nickel foam (NF) using carbon dots (CDs) as a directing agent. The strong bonding between the CDs and metals provides additional active sites, giving 0.5CDs-NiCoP/NF excellent electrocatalytic hydrogen evolution performance in environments ranging from acidic to basic. Moreover, the unique structure of 0.5CDs-NiCoP/NF endows this catalyst with low Tafel slopes of 73, 146 and 74 mV dec-1 for HER in acidic, neutral and alkaline conditions, respectively. This performance exceeds that of numerous other reported non-precious HER catalysts. In summary, this work offers a novel and efficient strategy for the design and synthesis of low-cost, efficient, and robust transition metal phosphides (TMPs) electrocatalysts.

Improved lithium-ion battery performance by introducing oxygen-containing functional groups by plasma treatment.

Metal sulfides are often used as cathode materials for lithium-ion batteries (LIBs) owing to their high theoretical specific capacity; however, excessively fast capacity decay during charging/discharging and rapid shedding during cycling limits their practical application in batteries. In this study, we proposed a strategy using plasma treatment combined with the solvothermal method to prepare cobalt sulfide (Co1-xS)-carbon nanofibers (CNFs) composite. The plasma treatment could introduce oxygen-containing polar groups and defects, which could improve the hydrophilicity of the CNFs for the growth of the Co1-xS, thereby increasing the specific capacity of the composite electrode. The results show that the composite electrode present a high discharge specific capacity (839 mAh g-1at a current density of 100 mA g-1) and good cycle stability (the capacity retention rate almost 100% at 2000 mA g-1after 500 cycles), attributing to the high conductivity of the CNFs. This study proves the application of plasma treatment and simple vulcanization method in high-performance LIBs.

Porous nanotube networks of SnO2/MoO3@Graphene as anodes for rechargeable lithium-ion batteries.

We successfully fabricated composite porous nanotube networks of SnO2/MoO3@Graphene through electrospinning and used it as lithium-ion battery anodes. When the ratio of SnO2 to MoO3 is 1:1, the composite of SnO2/MoO3 delivers a high capacity of 560 mAh g-1 at 1 A g-1 after 300 cycles. The excellent electrochemical performance was attributed to the unique 3D porous nanotube network structure which could provide more transmission channels for Li+ ions and electrons, and provide more electrochemical reaction sites. The hybrid nanostructure can also weaken local stress and relieve volume expansion which contributes to the attractive cycling stability. Moreover, we added a small amount of graphene in the composite to improve the electrical conductivity, and the SnO2/MoO3@Graphene composite showed favorable electrochemical performance (798 mAh g-1 at 1 A g-1 after 300 cycles). Finally, electrospinning technology is a simple and efficient synthesis strategy, which can promote the preparation of different types of metal oxide composite materials and has good application prospects.