Cu-Doped MoSi2N4 Monolayer as a Potential NH3 Sensor

Cu doped MoSi₂N₄ monolayer (Cu-MoSi₂N₄) was firstly proposed to analyze adsorption performances of common gas molecules including O₂, N₂, CO, NO, NO₂, CO₂, SO₂, H₂O, NH₃ and CH₄ via density functional theory (DFT) combining with non-equilibrium Green's function (NEGF). The electronic transport calculations indicate that Cu-MoSi₂N₄ monolayer has high sensitivity for CO, NO, NO₂ and NH₃ molecules. However, only NH₃ molecule adsorbs on the Cu-MoSi₂N₄ monolayer with moderate strength (−0.55 eV) and desorbs at room temperature (2.36×10⁻³ s). Thus, Cu-MoSi₂N₄ monolayer is demonstrated as a potential NH₃ sensor.     

Density functional theory study on sensing properties of g-C3N4 sheet to atmospheric gasses: Role of zigzag and armchair edges

The ability of the polymer-based graphitic carbon nitride (g-C₃N₄) as a gas sensor toward NO, NO₂, CO, CO₂, SO₂, SO₃, and O₂ gasses is assessed using density functional theory (DFT) calculations in terms of energetic and electronic transport characteristics. In particular, this study is aimed to explore the role of zigzag and armchair edges of the g-C₃N₄ sheet on sensing performances. The electronic properties of adsorption systems, such as Bader charge analysis, band gaps, work function, and density of states (DOS), are used to understand the interaction between the adsorbed gas molecules and the g-C₃N₄ sheet. Our calculated results indicate that SOx (SO₃ and SO₂) gasses have higher adsorption energies on the g-C₃N₄ sheet than other gasses. Furthermore, the transport properties, such as current–voltage (I-V) and resistance-voltage (R-V) curves along the zigzag and armchair directions are calculated using the non-equilibrium Green's function (NEGF) method to understand the performance of the g-C₃N₄ sheet as a prominent conductive/resistive sensor. The I-V/R-V results indicate that the zigzag g-C₃N₄ sheet has excellent sensing ability toward SOx gasses at low applied voltages. However, the presence of H₂O degrades the sensing performance of the armchair g-C₃N₄ sheet. Theoretical recovery time has also been calculated to evaluate the reusability of g-C₃N₄ sheet-based gas sensors. Our results reveal that the zigzag g-C₃N₄ sheet-based sensing device has a remarkably high sensitivity (>300%) and selectivity toward SOx gasses and has the potential to work in a complex environment.     

二维导电金属有机骨架材料

金属有机骨架(MOFs)是由金属离子或簇与有机配体以配位键组装而成的晶态多孔材料,其高的孔隙率及功能可设计性使其广泛应用于各种领域。然而,传统MOFs多数电导率非常低,这严重制约了其在电学相关领域的发展。近年来,导电金属有机骨架尤其是二维导电金属有机骨架(2D ECMOFs)材料因其结构中独特的π-π堆积及π-d共轭作用而呈现出半导体甚至类金属的电子输运性质而受到广泛关注,已在传感器、电子器件、电催化、电池和超级电容器等电学和能源相关领域展现出潜在的应用价值。本文将从2D ECMOFs的导电机理、结构、合成方法及应用等方面对近几年该领域的重要进展进行综述,并对其未来发展的挑战和机遇提出展望。     

Monitoring Imidazoline Derivatives via Functionalized Nano-Potentiometric Platforms in Aqueous Humor and Dosage Forms

The determination of two imidazoline derivatives [oxymetazoline HCl (OXY) and xylometazoline HCl (XYLO)] was described using different potentiometric platforms. The first electrode type was constructed using tetraphenyl borate (TPB) as anionic exchanger with β-cyclodextrins (β-CD) as ionophore forming oxymetazoline-tetraphenyl borate (OXY-TPB) and xylometazoline-tetraphenyl borate (XYLO-TPB), respectively. The second electrode type was prepared by modification of the first type by conjugation with magnetic iron oxide nanoparticles (MNP) forming (OXY-MNP) and (XYLO-MNP). The synthesized electrodes were fully characterized. The effect of magnetic nano-sized particles as a highly dispersible material with β-CDs on the electrode characteristics was investigated and compared against the classical electrodes. The response time, working pH range and selectivity coefficients were studied. The functionalized nano-electrodes (OXY-MNP and (XYLO-MNP) were found to be more sensitive than the classical electrodes with linearity ranges (1×10⁻⁶–1×10⁻² M). The functionalized nano-electrodes were successfully applied for the in-line analysis of OXY and XYLO in pharmaceutical dosage forms and spiked rabbit aqueous humor samples with no prior extraction of treatment. This suggests the future use of these electrodes in clinical studies of both drugs of interest.     

Conductive 2D Metal-organic Framework (Co,NiCo, Ni) Nanosheets for Enhanced Non-enzymatic Detection of Urea

2D metal-organic framework (MOF) has potential applications in electrocatalysis owing to fast mass transfer, charge transfer and large specific surface area. Here, we had prepared three conductive 2D MOF based on Ni, NiCo and Co in a simple and rapid way. The 2D nanostructure of MOF was confirmed by SEM and TEM. The chemical composition was studied by XRD, Raman and XPS spectrum. The electrochemical oxidation and detection was investigated through cyclic voltammetry and current-time method. Their sensing performance for urea was determined by varying oxidation potentials and metal sites. The non-enzymatic Ni-, NiCo- and Co-MOF sensors had good catalytic activity for urea. Compared with NiCo- and Co-MOF, Ni-MOF had a wider linear range (0.5–832.5 μM), high sensitivity (1960 μA mM⁻¹ cm⁻²), low detection limit (0.471 μM), and fast response time. The sensors had well repeatability, reproducibility, and selectivity to specific interfering species. Furthermore, Ni- and NiCo-MOF modified electrode was also applied to detection of milk samples. The results showed that the recovery was satisfactory, which further confirmed the effectiveness of non-enzyme sensor. In general, the highly-sensitive 2D Ni- and NiCo-MOF modified electrode has great potential as nonenzymatic urea sensors for real samples detection in hydrogen energy, clinical diagnostics, and environmental protection, et al.     

A review on recent advances in hierarchically porous metal and metal oxide nanostructures as electrode materials for supercapacitors and non-enzymatic glucose sensors

The remarkable significance of electrode materials in industrial processes, energy, sustainability and diabetes monitoring has captivated scientists to develop advance nanomaterials for the benefit of life across the globe. Here in, the recent developments in nanostructured porous metal and metal oxide composite materials for supercapacitor applications and non-enzymatic glucose sensors (NEGS) has been extensively discussed. The essential and active electrode materials from the research and application perspective has been emphasized in detail. We have also evaluated the worthiness, taxonomical classification, efficiency, specific capacitance and sensitivity of these materials for the aforementioned potential applications. Eventually, we concluded the review by providing the aspect ratio, surface morphology, particle size and specific surface area of these materials that plays an indispensable role for their promising potential applications.     

Terpyridine-Functionalized Calixarenes: Synthesis,Characterization and Anion Sensing Applications

Lanthanide complexes have been developed and are reported herein. These complexes were derived from a terpyridine-functionalized calix[4]arene ligand, chelated with Tb³⁺ and Eu³⁺. Synthesis of these complexes was achieved in two steps from a calix[4]arene derivative: (1) amide coupling of a calix[4]arene bearing carboxylic acid functionalities and (2) metallation with a lanthanide triflate salt. The ligand and its complexes were characterized by NMR (¹H and ¹³C), fluorescence and UV-vis spectroscopy as well as MS. The photophysical properties of these complexes were studied; high molar absorptivity values, modest quantum yields and luminescence lifetimes on the ms timescale were obtained. Anion binding results in a change in the photophysical properties of the complexes. The anion sensing ability of the Tb(III) complex was evaluated via visual detection, UV-vis and fluorescence studies. The sensor was found to be responsive towards a variety of anions, and large binding constants were obtained for the coordination of anions to the sensor.     

Sensing nanomaterials of wearable glucose sensors

The metabolic disorder of glucose in human body will cause diseases such as diabetes and hyperglycemia.Hence the determination of glucose content is very important in clinic diagnosing.In recent years,researchers have proposed various non-invasive wearable sensors for rapid and real-time glucose monitoring from human body fluids.Unlike those reviews which discussed performances,detection environments or substrates of the wearable glucose sensor,this review focuses on the sensing nanomaterials since they are the key elements of most wearable glucose sensors.The sensing nanomaterials such as carbon,metals,and conductive polymers are summarized in detail.And also the structural characteristics of different sensing nanomaterials and the corresponding wearable glucose sensors are highlighted.Finally,we prospect the future development requirements of sensing nanomaterials for wearable glucose sensors.This review would give some insights to the further development of wearable glucose sensors and the modern medical treatment.     

Electrochemical Peptide-Based Sensors for Foodborne Pathogens Detection

Food safety and quality control pose serious issues to food industry and public health domains, in general, with direct effects on consumers. Any physical, chemical, or biological unexpected or unidentified food constituent may exhibit harmful effects on people and animals from mild to severe reactions. According to the World Health Organization (WHO), unsafe foodstuffs are especially dangerous for infants, young children, elderly, and chronic patients. It is imperative to continuously develop new technologies to detect foodborne pathogens and contaminants in order to aid the strengthening of healthcare and economic systems. In recent years, peptide-based sensors gained much attention in the field of food research as an alternative to immuno-, apta-, or DNA-based sensors. This review presents an overview of the electrochemical biosensors using peptides as molecular bio-recognition elements published mainly in the last decade, highlighting their possible application for rapid, non-destructive, and in situ analysis of food samples. Comparison with peptide-based optical and piezoelectrical sensors in terms of analytical performance is presented. Methods of foodstuffs pretreatment are also discussed.