Mechanism Insights in Anticorrosion Performance of Waterborne Epoxy Coatings Reinforced by PEI-Functionalized Boron Nitride Nanosheets.

Functionalized hexagonal boron nitride nanosheets (BNNSs) have arisen as compelling anticorrosive additives, yet the precise mechanism of their corrosion resistance enhancement in coatings remains unclear. Here, polyethylenimine functionalized BNNSs (PEI-BNNSs) with approximately 6-11 layers were prepared through a "one-step" method. Then, the PEI-BNNSs/Waterborne epoxy (WEP) composite coatings were incorporated via the waterborne latex blending method for the anticorrosion of the Q235 substrate. The impedance modulus (|Z|f = 0.01 Hz) of 0.5 wt % PEI-BNNSs/WEP composite coating soaked in 3.5 wt % NaCl solution for 35 days increased by 4 orders of magnitude compared to pure WEP coating, exhibiting exceptional long-term resistance against corrosion. The positron annihilation lifetime spectroscopy and corrosion product analysis demonstrated that the reinforced anticorrosion capabilities are not solely ascribed to the "tortuous path effect" arising from BNNSs impermeability. These mechanisms also encompass the reduction in free volume fraction and radius of the free volume cavities within the composite coating brought about by the PEI molecules. Additionally, the increase in coating adhesion, promoted by PEI, plays an important role in augmenting the barrier properties against corrosive agents. This study provided a full comprehension of the role played by functionalized BNNSs in fortifying the anticorrosion attributes of WEP coatings.

Preparation of Ag3PO4/α-Fe2O3 hybrid powders and their visible light catalytic performances.

The inefficiency of conventional photocatalytic treatment for removing rhodamine B is posing potential risks to ecological environments. Here, we construct a highly efficient photocatalyst consisting of Ag3PO4 and α-Fe2O3 hybrid powders for the treatment of rhodamine B. Ag3PO4 nanoparticles (nanoparticles, about 50 nm) are uniformly dispersed on the surface of α-Fe2O3 microcrystals (hexagonal sheet, about 1.5 µm). The Ag3PO4-deposited uniformity on the α-Fe2O3 surface first increased, then decreased on increasing the hybrid ratio of Ag3PO4 to α-Fe2O3. When the hybrid ratio of Ag3PO4 to α-Fe2O3 is 1 : 2, the distribution of Ag3PO4 particles on the sheet α-Fe2O3 is more uniform with excellent Ag3PO4/α-Fe2O3 interface performance. The catalytic degradation efficiency of hybrids with the introduction of Ag3PO4 nanoparticles on the α-Fe2O3 surface reached 95%. More importantly, the hybrid material exhibits superior photocatalytic stability. Ag3PO4/α-Fe2O3 hybrids have good reusability, and the photocatalytic efficiency could still reach 72% after four reuses. The excellent photocatalytic activity of the as-prepared hybrids can be attributed to the heterostructure between Ag3PO4 and α-Fe2O3, which can effectively inhibit the photoelectron-hole recombination and broaden the visible light response range.

A paper-based lateral flow sensor for the detection of thrombin and its inhibitors.

Thrombin is a biomarker of blood-related diseases. Its detection and inhibitor screening are of great significance in the fields of medical and biological research. Herein, a novel paper-based lateral flow sensor for thrombin detection and inhibitors screening is developed. The formation of cross-links of fibrin from fibrinogen during the blood clotting process can efficiently capture water molecules. Based on the principle, in the presence of thrombin, the water of the plasma solution cannot flow along with the test paper as the water molecules are trapped in the fibrin. Upon the inactivation of thrombin by the inhibitors, water can flow along the test paper. The detection limit of thrombin reaches about 16.1 mU/mL and the sensing platform also exhibits excellent selectivity, reproducibility, and stability. Furthermore, the inhibition efficiency of argatroban, a clinical drug used as a thrombin inhibitor, is also successfully investigated using the assay. Overall, this strategy exhibits the advantages of the specific enzymatic reaction, low-cost, and label-free detection of thrombin with high sensitivity and remarkable specificity. This method is also competent to facilitate the screening of thrombin inhibitors, which is promising in the discovery of therapeutic drugs for thrombus-related diseases.

Wet chemical controllable synthesis of hematite ellipsoids with structurally enhanced visible light property.

A facile and economic route has been presented for mass production of micro/nanostructured hematite microcrystals based on the wet chemical controllable method. The as-prepared samples were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-Vis absorption spectroscopy. The results showed that the product was mesoporous α -Fe2O3 and nearly elliptical in shape. Each hematite ellipsoid was packed by many α -Fe2O3 nanoparticles. The values of vapor pressure in reaction systems played vital roles in the formation of porous hematite ellipsoids. Optical tests demonstrated that the micro/nanostructured elliptical hematite exhibited enhanced visible light property at room temperature. The formation of these porous hematite ellipsoids could be attributed to the vapor pressure induced oriented assembling of lots of α -Fe2O3 nanoparticles.

Facile sonochemical synthesis of hierarchical porous CuO nanotablets.

Hierarchical semiconductor CuO nanotablets with pores have been fabricated on a large scale by a facile and one-pot sonochemical process using the copper acetate and ammonia aqueous solution as precursor in the absence of surfactants or additives. The as-synthesized products were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM), selected area electron diffraction (SAED), and N2 physisorption. The results reveal that porous tablet-shaped CuO nanostructures composed of nanoribbons possess a monoclinc phase CuO with the average diameters about 200 nm and around 50 nm in thickness. The Brunnauer-Emmett-Teller (BET) specific surface area and the single point adsorption total pore volume were measured to be 26.8 m2/g and 0.083 cm3/g, respectively. The band-gap energies were estimated to be 2.52 eV from a UV-vis absorption spectrum, which showed the quantum size effects of the nanosized semiconductors. A possible mechanism for porous CuO nanotablets was discussed.

One-pot sonochemical fabrication of hierarchical hollow CuO submicrospheres.

Hierarchical hollow CuO submicrospheres have been fabricated on a large scale by a facile one-pot sonochemical process in the absence of surfactants and additives. The as-prepared products were investigated by XRD, FESEM, EDX, TEM, SAED, HRTEM and BET nitrogen adsorption-desorption isotherms. The results reveal that hollow pumpkin-shaped structures possess a monoclinic phase CuO with the diameters ranging from 400 to 500 nm, and their walls with around 45 nm in thickness are composed of numerous single crystalline CuO nanoribbons with a width of about 8 nm. The BET specific surface area of the as-synthesized CuO hollow structures was measured to be 59.60 m(2)/g, and the single point adsorption total pore volume was measured to be 0.1036 cm(3)/g. A possible growth mechanism for the formation of hierarchical hollow CuO structures was proposed, which is considered to be a sonohydrolysis - oriented aggregation - Ostwald ripening process. The novel hollow CuO spherical structures may utilize applications in biosensors, photonics, electronics, and catalysts.