Latest ArticlesElectrocatalytic N2 reduction to ammonia is a fascinating alternative to Haber-Bosch process and also considered as an energy storage method. This work, Fe doped MoS2/carbon cloth (CC) has been studied on the electro-catalysis fix nitrogen indicating the doped Fe can indeed enhance the MoS2 material ability. Compared with MoS2/CC, Fe-Mo-S-3/CC not only increases 10 times in the rate of production ammonia, but also 5 times in Faraday efficiency.
In the work, we successfully explore a two-step hydrothermal method for scalable synthesis of the hybrid sodium titanate (NaTi8O13/NaTiO2) nanoribbons well in-situ formed on the multi-layered MXene Ti3C2 (designed as NTO/Ti3C2). Benefiting from the inherent structural and componential superiorities, the resulted NTO/Ti3C2 composite exhibits long-duration cycling stability and superior rate behaviors when evaluated as a hybrid anode for advanced SIBs, which delivers a reversible and stable capacity of ~82 mAh/g even after 1900 cycles at 2000 mA/g for SIBs.
Direct infusion mass spectrometry (DIMS) is a powerful technique in clinical diagnosis for screening neonatal amino acid metabolic disorders from dried blood spots (DBS). However, DIMS sometimes generated false-positive results for analysis of amino acids. In this work, we utilized a stable isotope derivatization method, combining with liquid chromatography tandem mass spectrometry (SID-LC-MS), to improve the specificity for screening amino acids in DBS specimens. A pair of isotope reagents, p-(dimethylamino)phenyl isothiocyanate (DMAP-NCS) and 4-isothiocyanato-N, N-bis(methyl-[2H2])aniline ([2H4]DMAP-NCS), was synthesized and used to label amino acids in DBS specimens. The [2H4]DMAP-NCS labelled amino acid standards were used as internal standards to compensate the matrix effect. This method was validated by measuring linearity, recovery and accuracy. The results showed that the developed SID-LC-MS method can be used for sensitive and selective determination of 12 diagnostically important amino acids in DBS specimens.
In addition to the theoretical research, direct ethanol fuel cells have great potential in practical applications. The performance of direct ethanol fuel cells largely depends on the electrocatalysts. Pt-based electrocatalysts have been promising candidates for advancing direct ethanol fuel cells for its high catalytic activity and great durability. Here, a PtSn catalyst with unique three-dimensional porous nanostructure has been designed and synthesized via a two-step liquid phase reduction reaction. Sn formed a self-supporting framework in PtSn alloy particles (~3.5 nm). In ethanol electro-oxidation reaction, the PtSn catalyst exhibited high mass activity and excellent recycling time compared with that of Pt/C. After the morphology characterization before and after potential cycling, the PtSn alloy-based nano-catalyst showed good stability. The PtSn catalysts effectively avoid structural instability due to the external carriers, and prolong the leaching time of Sn. In addition, the introduction of a certain amount of Sn can also solve the poisoning phenomenon of active sites on Pt surface. The design strategy of porous alloy nano-catalyst sheds light on its applications in direct ethanol fuel cells.
An iron (Ⅲ) cluster, namely [Fe10(μ3-O)8L8(NO3)6] (1), has been synthesized by treatment of Fe (NO3)3·9H2O with 3, 5-dimethyl-1-(hydroxymethyl)-pyrazole (HL) under ambient temperature. The core skeleton of {FeⅢ10} can be regarded as a pear-like cage with eight triangular {FeⅢ3(μ3-O)} units, in which each three FeⅢ centers is held together by one μ3-O2- group with FeⅢ centers as corner-sharing triangle units. Importantly, {FeⅢ10} cluster is not only stable in solid state but also in solution, which is confirmed by powder X-ray diffraction (PXRD) pattern and electrospray ionization mass spectrometry (ESI-MS), respectively. Furthermore, 1 shows antiferromagnetic exchange behavior arising from the interactions between the iron(Ⅲ) centers.
Pathogen infection is the main cause of human morbidity and death. Traditional antibiotics usually sterilize bacteria in chemical ways, which tends to develop serious antibiotic resistance. Cationic polymers exhibit good bacterial inhibition with less resistance, but often face severe cytotoxicity toward normal cells. The optimization of polymeric antimicrobials for enhanced bactericidal capacity and improved biocompatibility is quite meaningful. In addition, photodynamic therapy (PDT) is a therapeutic modality with less susceptibility to develop resistance. Herein, a typical commercial polymeric antimicrobial, polyhexamethylene guanidine (PHMG) was selected for current proof-of-concept optimization due to its excellent bactericidal capacity but moderate biocompatibility. Eosin-Y (EoS) was copolymerized to afford EoS-labeled polymer conjugates, poly(2-(dimethylamino) ethyl methacrylate-co-eosin), P(DMAEMA-co-EoS), which was conjugated with PHMG to afford a novel polymeric antimicrobial, P(DMAEMA-co-EoS)-b-PHMG-b-P(DMAEMA-co-EoS), noted as PEoS-PHMG. It could efficiently kill broad-spectrum bacteria by physical damage and photodynamic therapy. Compared with PHMG, the bacterial inhibition of PEoS-PHMG was potentiated after the functionalization. Furthermore, PEoS-PHMG exhibited low cytotoxicity and minimal hemolysis, which was demonstrated by cell viability assays toward LO2 cells and RAW 264.7 cells as well as hemolytic assays against red blood cells. These results confirmed that the resultant PEoS-PHMG could act as promising alternative antibacterial materials with excellent broad-spectrum bacterial inhibition and favorable biocompatibility.
A highly sensitive electrochemiluminescence (ECL) biosensing method was developed for monitoring casein kinase Ⅱ (CK2) at subcellular level via bio-bar-code assay. A bio-bar-code probe (h-DNA/AuNPs/pDNA) prepared by conjugating phosphorylated DNA (p-DNA) and hairpin DNA (h-DNA) onto gold nanoparticles (AuNPs) was used as a carrier for ECL signal reagent (Ru(phen)32+) while a specific peptide was used as a recognition substance. A gold ultramicroelectrode with a diameter of 400 nm was fabricated and then modified with the specific peptide via self-assembly technique to obtain peptide modified gold ultramicroelectrode. The peptide on gold ultramicroelectrode was phosphorylated in the presence of CK2 and adenosine 5'-triphosphate, and then the phosphorylated peptide was integrated with the h-DNA/AuNPs/p-DNA through a process mediated by zirconium cations (Zr4+), and finally Ru(phen)32+ was intercalated into h-DNA. A "signal on" ECL method was developed for the detection of CK2 in the range of 0.005-0.2 U/mL with a detection limit of 0.001 U/mL. Additionally, combined efficient subcellular phosphorylation in vivo with bio-bar-code-based ECL biosensing method, the ECL method was further applied to monitor CK2 at subcellular level without tedious subcellular fractionation. It was found that the concentration of CK2 by inserting the peptide modified gold ultramicroelectrode into the nucleus was higher than that into cytoplasm of HeLa cells. A distinct heterogeneity among CK2 concentrations in single cells was observed for cellular heterogeneity assessment.
Developing a fast, sensitive and convenient method for the detection of hydroxyl radicals (·OH) in the atmosphere could help us know the precursor levels of atmospheric species and control air pollution. In this work, the carbon fiber paper (CFP) functionalizing with a kind of covalent organic frameworks (COFs), formed from 1, 3, 5-triformylphloroglucinol (Tp) and benzidine (BD) (COF(TpBD)), was firstly used a new platform for ·OH trapping and detection. The COF(TpBD) modified CFP was acted as a filter to impregnate salicylic acid (SA) and a detector to detect 2, 5-dihydroxybenzoic acid (2, 5-DHBA) which was produced from the reaction between the impregnated SA and ·OH in the atmosphere. This method provided a linearity for 2, 5-DHBA from 5.0×10-14 mol/L 1.0×10-9 mol/L with a detection limit of 6.9×10-15 mol/L, which is corresponding to the amount of ·OH from 3.0×107 to 6.0×1011 molecules/cm3 with the detection limit of 4.1×106 molecules/cm3. This COF(TpBD)-CFP platform has been successfully applied for the detection of ·OH concentration under different conditions of Yangzhou when the sampling time was shortened to 30 min. This work has provided a new method for atmospheric ·OH detection with excellent sensitivity, simplicity, and high speed.
Ru and Co are highly dispersed on the surface of TiO2 nanoparticles with an easy coprecipitation method to fabricate a novel Ru-based catalyst (Ru/Co-TiO2). The fabricated Ru/Co-TiO2 catalyst exhibits superior catalytic performance for promoting NaBH4 hydrolysis in alkaline medium, showing an impressive hydrogen generation rate per gram Ru as high as 172 L min-1 gRu-1, which is better than most of recently reported Ru-based catalysts. In addition, the fabricated Ru/Co-TiO2 catalyst also shows excellent durability in cycle use, with only 2.9% activity loss after being used for 5 cycles.These advantages make the developed Ru/ Co-TiO2 catalyst a potential choice for promoting hydrogen generation from NaBH4 hydrolysis.
The morphological and structural design provides an efficient protocol to optimize the performance of gas sensing materials. In this work, a gas sensor with high sensitivity for triethylamine (TEA) detection is developed based on p-type NiCo2O4 hierarchical microspheres. The NiCo2O4 microspheres, synthesized by a hydrothermal route, have a three-dimensional (3D) urchin-like structure assembled by nanorod building blocks. The structure-property correlation has been investigated by powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscope, scanning electron microscope, N2 adsorption-desorption tests and comprehensive gas sensing experiments. The influence of calcination temperature on the morphological structure and sensing performances has been investigated. Results reveal that the material annealed at 300 ℃ has a very large specific surface area of 125.27 m2/g, thereby demonstrating the best TEA sensing properties including high response and low limit of detection (145 ppb), good selectivity and stability. The further increase of the calcination temperature leads to the collapse of the 3D hierarchical structure with significantly decreased surface area, which is found to decline the sensing performances. This work indicates the promise of ternary p-type metal oxide nanostructures for application in highly sensitive gas sensors.
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