Microenvironment Control over Electrocatalytic Activity of g-CN/2H-MoS Superlattice-like Heterostructures for Hydrogen Evolution.

Microenvironments in heterogeneous catalysis have been recognized as equally important as the types and amounts of active sites for regulating catalytic activity. Two-dimensional (2D) nanospaces between van der Waals (vdW) gaps of layered materials provide an ideal microenvironment to create novel functionalities. Here, we explore a facile method for fabricating g-CN/2H-MoS superlattice-like heterostructures based on thermochemical intercalation and polymerization reactions of formamide within enlarged vdW gaps of 2H-MoS nanosheets without any transfer process.

Group polarization calls for group-level brain communication.

Group of people shows the shift towards extreme of decision-making as opposed to individuals. Previous studies have revealed two directions of group polarization, i.e.

Non enzymatic fluorometric determination of glucose by using quenchable g-CN quantum dots.

A non-enzymatic fluorometric assay is described for the determination of glucose. The method is based on the use of g-CN quantum dots (QDs) that have good water solubility. The QDs were synthesized by a one-step solvothermal process using formamide as precursor.

Probing Conformation Change and Binding Mode of Metal Ion-Carboxyl Coordination Complex through Resonant Surface-Enhanced Raman Spectroscopy and Density Functional Theory.

Understanding carboxyl-metal ligand interaction has great significance in analytical chemistry. Herein, we use resonant surface-enhanced Raman scattering (SERS) to probe the physiochemical interaction and conformation change in several metal ion-carboxyl coordination complex systems adsorbed on the surface of plasmonically resonant metal nanostructures. Our SERS results and density function theory calculations jointly reveal that low-valence metal ions (such as K and Pb) tend to bind to the carboxyl active site of a Raman tag molecule, 4-mercaptobenzoic acid (4-MBA), in a unidentate binding mode of low binding energy whereas high-valence metal ions (such as Fe) favor a bidentate binding mode of relatively high binding energy.

Two-dimensional nanomaterial based sensors for heavy metal ions.

Two-dimensional (2D) nanomaterials are promising building blocks for sensors due to their unique physical, chemical, electronic, and optical properties. This review (with 253 references) first summarizes the historical developments of 2D nanomaterials and discusses the advantages of 2D nanomaterials when applied for constructing sensors. Next, their properties are discussed, with subsections on electronic, optical, mechanical and chemical properties.

Covalent functionalization of MoS nanosheets synthesized by liquid phase exfoliation to construct electrochemical sensors for Cd (II) detection.

Surface functionalization is an effective strategy in the precise control of electronic surface states of two-dimensional materials for promoting their applications. In this study, based on the strong coordination interaction between the transition-metal centers and N atoms, the surface functionalization of few-layer MoS nanosheets was successfully prepared by liquid phase exfoliation method in N, N-dimethylformamide (DMF), 1-methyl-2-pyrrolidinone, and formamide. The cytotoxicity of surface-functionalized MoS nanosheets was for the first time evaluated by the methylthiazolyldiphenyl-tetrazoliumbromide assays.

A versatile fluorescent biosensor based on target-responsive graphene oxide hydrogel for antibiotic detection.

A fluorescent sensing platform based on graphene oxide (GO) hydrogel was developed through a fast and facile gelation, immersion and fluorescence determination process, in which the adenosine and aptamer worked as the co-crosslinkers to connect the GO sheets and then form the three-dimensional (3D) macrostructures. The as-prepared hydrogel showed high mechanical strength and thermal stability. The optimal hydrogel had a linear response for oxytetracycline (OTC) of 25-1000μg/L and a limit of quantitation (LOQ) of 25μg/L.

Two-dimensional MoS: A promising building block for biosensors.

Recently, two-dimensional (2D) layered nanomaterials have trigged intensive interest due to the intriguing physicochemical properties that stem from a quantum size effect connected with their ultra-thin structure. In particular, 2D molybdenum disulfide (MoS), as an emerging class of stable inorganic graphene analogs with intrinsic finite bandgap, would possibly complement or even surpass graphene in electronics and optoelectronics fields. In this review, we first discuss the historical development of ultrathin 2D nanomaterials.

Three-Dimensional Porous HxTiS2 Nanosheet-Polyaniline Nanocomposite Electrodes for Directly Detecting Trace Cu(II) Ions.

In the present work, three-dimensional porous HxTiS2 nanosheet-polyaniline (PANI) nanocomposites were first synthesized by a two-step method. First, HxTiS2 ultrathin nanosheets were prepared by the lithium intercalation and exfoliation method, followed by the surface polymerization reactions of aniline. The influences of the amount of HxTiS2 nanosheets on the nanocomposite morphology and electrochemical performances of the nanocomposites modified glass carbon electrode (HxTiS2 nanosheet-PANI/GCE) were investigated.

Electrochemical DNA sensor for specific detection of picomolar Hg(II) based on exonuclease III-assisted recycling signal amplification.

An ultrasensitive methodology was successfully developed for the quantitative detection of picomolar Hg(2+) based on the combination of thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and exonuclease III-aided recycling signal amplification. Single-strand probe DNA was immobilized on an Au electrode via an Au-S bond. In the presence of Hg(2+), the probe DNA hybridized with the target DNA containing four thymine-thymine (T-T) mismatches via the Hg(2+)-mediated coordination of T-Hg(2+)-T base pairs.