Near-infrared Responsive Photoelectrochemical Biosensors

Near-infrared (NIR) light-driven photoelectrochemical (PEC) sensing is a highly promising analytical technique, especially for in situ bioanalysis, due to the deep penetration capability and minimal invasiveness of NIR light. In this mini review, we provide a brief overview of recently developed NIR PEC sensors, focusing on NIR light-responsive materials and the representative applications of this type of PEC sensor. Future perspectives for NIR PEC sensors are also described.     

Fire retarded polyurethane foam composites based on steel slag/ammonium polyphosphate system: A novel strategy for utilization of metallurgical solid waste

A series of FR-RPUF composites were prepared by a one-step water foaming process with ammonium polyphosphate (APP) and steel slag (SS) as flame retardants. Thermogravimetric analysis (TG), limiting oxygen index (LOI), UL-94 vertical combustion test, microscale combustion calorimetry (MCC), TG-Fourier transform infrared spectrometry (TG-FTIR), scanning electron microscopy (SEM), Raman spectra and FTIR were used to investigate the thermal stability, flame retardancy, combustion performance, gas phase products, and char residue morphology of FR-RPUF composites. TG test results showed that the initial decomposition temperature (T_-5wt%) and char residue rate at 700°C of RPUF/APP/SS composites were significantly enhanced by the addition of APP and SS, and the thermal stability of the composites was improved. Flame retardant test results confirmed the significantly increased LOI values of RPUF/APP/SS composites with V-0 rating. TG-FTIR also confirmed the obviously decreased release of toxic gases and flammable gases in the combustion of RPUF/APP/SS composites. SEM and Raman spectra of char residues for the composites suggested that APP/SS system improved the compactness and graphitization degree of char layer for RPUF/APP/SS composite. The above researches provide a new strategy for the utilization of SS in fire safety engineering.     

Flexible strain sensor with ridge-like microstructures for wearable applications

The flexible stretchable sensors have great potential for implementation in various applications, such as intelligent soft robots, health monitoring, and motion detection. However, most of the flexible stretchable sensors with microstructures and high sensitivities are fabricated by expensive templates and complex processes. In consideration of large-scale fabrication, a low cost and efficient way is in great demand. Herein, electroless plating on Nafion films with decent swelling ratios are proposed to fabricate stretchable sensors with wrinkle-structured electrodes. By adding isopropanol (IPA) to the electroless plating process, the H₂O-IPA sensor with larger swelling ratio shows deeper surface wrinkles, higher surface roughness, and better sensitivity to strain. At the same time, the H₂O-IPA sensor exhibit good durability (500 cycles). By mounting the sensor on the joint of human finger, the motion of the finger bending and even the bending degree can be accurately detected, indicating the potential use in the field of wearable devices and soft electronic skins.     

Insight mechanism of nano iron difluoride cathode material for high-energy lithium-ion batteries: a review

Journal of Solid State Electrochemistry - Iron(II) fluoride (FeF2) is a promising candidate as the cathode material for lithium-ion batteries (LIBs) due to its quite high theoretical energy density...     

A DFT Study on the Binuclear Copper(I)-Catalyzed Synthesis Mechanism of 1,2,3-Triazolo[1,5-c]Pyrimidine via Interrupted Click and Ketenimine Rearrangement

In this paper, the mechanism of the full catalytic cycle for binuclear Cu(I)-catalyzed sulfonyl azide-alkyne cycloaddition reaction for the synthesis of triazolopyrimidines was rationalized by density functional theoretical (DFT) calculations. The computed reaction route consists of: (a) formation of dicopper intermediates, including C−H activation of terminal alkyne, 3+2 ring cycloaddition and ring-reducing reaction and transmetalation, (b) interrupted CuAAC reaction, including di-copper catalyzed ring-opening of 2H-azirines and C−C bond formation to generate the copper-triazoles and -ketenimines, (c) two-step C−N cross-coupling and following (d) multi-step hydrogen transfer by the hydrogen bonding chain of water to promote the C−N formation and another C−N cleavage through the removal of p-tolyl sulfonamides. Our DFT results indicate that the multi-step hydrogen transfer process is the rate-determining step along the potential energy surface profile. The explicit water model was used for systematic determination of barrier for C−C cross-coupling, C−N bond formation and cleavage, and p-tolylsulfonamide removal. A critical insight in the interrupted CuAAC reaction was proposed. Further prediction interprets H₂O hydrogen bond chain plays an important role in C−N bond formation and cleavage, and the removal of p-tolylsulfonamide. This may have fundamental guidance on the design of 1, 5-herterocyclic functionalized triazolopyrimidines via interrupted CuAAC rearrangement reaction, as well as hydrogen bond chain of water.     

热熔灌输法制备三维骨架支撑金属锂复合负极

金属锂因具有极高的理论比容量(3860 mAh/g)和最低的电化学势(相对于标准氢电极为-3.04 V),被认为是下一代高比能锂离子电池的首选负极材料。然而,金属锂负极在电池循环过程中发生的刺状枝晶生长和体积变化等问题严重阻碍了其产业化应用进程。近年来研究表明,通过在金属锂中引入具有三维(3D)结构的宿主骨架,不但能有效抑制锂枝晶的生长,而且可以缓解金属锂负极的体积变化,从而提高金属锂电池的循环性能与安全性。因此,设计3D骨架/金属锂复合负极被认为是一种能有效解决金属锂问题的新兴策略。本文综述了热熔灌输法制备3D骨架/金属锂复合负极的研究进展。首先讨论了当前基于3D骨架的预存金属锂技术,然后着重分析了热熔灌输策略中3D骨架锂润湿性的影响因素,以及不同3D骨架修饰特征和改性方法。最后对3D骨架/金属锂复合负极和热熔灌输策略现存问题进行了总结并提出未来的发展方向。     

Effects of High Pressure on the Surface Plasmon Resonance of Copper and Silver Nanocrystals

We used a diamond anvil cell(DAC) to control the deformation of synthesized copper nanorods and silver nanoparticles. And we measured the surface plasmon resonance of copper nanorods and silver nanoparticles, which exhibit redshifts or blueshifts. The surface plasmon resonance shows an abnormal blue shift for both copper nanorods and silver nanoparticles. The solvents of copper nanorods and silver nanoparticles are n-hexane and water, where the pressure loads include quasi-hydrostatic and non-hydrostatic.     

Spatiotemporally-regulated multienzymatic polymerization endows hydrogel continuous gradient and spontaneous actuation

There are several natural materials which have evolved functional gradients,ingeniously attaining maximal efficacy from limited components.Herein,we utilized the spatiotemporal distribution of initiator acetylacetone to regulate the multienzyme polymerization and fabricate a chitosan-polymer hydrogel.The temporal priority order of acetylacetone was higher than phenolmodified chitosan by density functional theory calculation.The acetylacetone within the gelatin could gradually diffuse spatially into the chitosan hydrogel to fabricate the composite hydrogel with gradient network structure.The gradient hydrogel possessed a transferring topography from the two-dimensional pattern.A continuously decreased modulus along with acetylacetone diffusion was confirmed by atomic force microscope-based force mapping experiment.The water-retaining ability of various regions was confirmed by low-field nuclear magnetic resonance(NMR)and thermogravimetric analysis(TG)analysis,which led to the spontaneous actuation of gradient hydrogel with maximum 1821°/h curling speed and 227°curling angle.Consequently,the promising gradient hydrogels could be applied as intelligent actuators and flexible robots.     

Dynamic assembly and biocatalysis-selected gelation endow self-compartmentalized multienzyme superactivity

Science China Chemistry - Cellular metabolism in multiple organelles utilizes compartmentalized multienzyme efficient catalysis to realize substance metabolism, energy conversion and immune...     

Neutral 1D Perovskite-Type ABX3 Phase Transition Material with a Narrowband Emission and Semiconductor Property

Cyclic organic amines are emerging as excellent building blocks to assemble organic–inorganic hybrid phase transition materials due to their flexible cyclic structure. Here, we have assembled a 1D organic-inorganic hybrid dielectric material C₅H₆NOPbBr₃ ( 1 ) by alloying the cyclic organic amine 3-hydroxypyridine. 1 displays a remarkable switchable dielectric response induced by an order-disorder transformation of the organic moiety, this transformation behaviour is confirmed by DSC and Hirshfeld surface measurements. More interestingly, 1 has a narrowband emission (FWHM=4.64 nm) at 590 nm; FWHM is a major quality figure for narrowband photodetectors. In addition, 1 exhibits semiconducting properties with an indirect bandgap of 2.78 eV by the analysis of the UV-Vis absorption results.