Itraconazole–Laponite: Kinetics and mechanism of drug release

A clay-drug nanohybrid was prepared by interfacial boundary ion exchange reaction, from which the release mechanism of a poorly water soluble drug, itraconazole, was studied systematically. The effect of cation types on drug release was investigated on the basis of a UPS 25 guide line and the effect of Laponite dissolution was also studied at pH = 1.2. To describe the release patterns, mathematical modeling was preformed using first-order, Elovich, parabolic diffusion, and power function equations.     

Graphene nanoribbons as a novel support material for high performance fuel cell electrocatalysts

Graphene nanoribbons (GNRs) were first used as a novel support material for Pt nanoparticles (NPs) based catalyst for methanol electro-oxidation. Upon oxidation and cutting of multiwall carbon nanotubes (MWCNTs), highly dispersive graphene oxide nanoribbons (GONRs) were obtained, on which metal ions such as PtCl₆²⁻ can be homogenously deposited. The hybrid catalyst of GNRs supported Pt NPs (Pt/GNR) was further prepared through facile in-situ chemical co-reduction, with a homogeneous distribution of Pt NPs (2–3 nm) on the nanoribbons. Compared to Pt/MWCNT and commercial Pt/XC72R catalysts, Pt/GNR hybrids show much larger electrochemically active surface area, higher electrochemical stability, and better CO tolerance towards electro-oxidation of methanol. Therefore, GNR is a promising alternative two-dimensional support material for electrocatalysts in direct methanol fuel cells.     

Flow-injection amperometric glucose biosensors based on graphene/Nafion hybrid electrodes

In this research, we demonstrated the fabrication of flow-injection amperometric glucose biosensors based on RGO/Nafion hybrids. The nanohybridization of the reduced graphene oxide (RGO) by Nafion provided the fast electron transfer (ET) for the sensitive amperometric biosensor platforms. The ET rate (k_s) and the charge transfer resistance (R_CT) of GOx-RGO/Nafion hybrids were evaluated to verify the accelerated ET. Moreover, hybrid biosensors revealed a quasi-reversible and surface controlled process, as confirmed by the low peak-to-peak (ΔE_p) and linear relations between I_p and scan rate (ν). Hybrid biosensors showed the fast response time of ∼3 s, the sensitivity of 3.8 μA mM⁻¹ cm⁻², the limit of detection of 170 μM, and the linear detection range of 2–20 mM for the flow-injection amperometric detection of glucose. Furthermore, interference effect of oxidizable species such as ascorbic acid (AA) and uric acid (UA) on the performance of hybrid biosensors was prevented at the operating potential of −0.20 V even under the flow injection mode. Therefore, the fast, sensitive, and stable amperometric responses of hybrid biosensors in the flow injection system make it highly suitable for automatically monitoring glucose.     

油温回升对含蜡原油添加纳米降凝剂改性影响

研究并分析了高含蜡原油经纳米降凝剂改性后油温回升对低温流变影响,并对改性后原油静态时效稳定性进行了室内实验研究。实验结果表明,高含蜡原油纳米降凝剂具有良好的降凝降粘效果,加剂后经65℃处理后,凝点降至17.5℃;油温回升后原油低温流动改善效果随回升温度的降低则更好,油温回升至35℃后,降温至30℃测试,凝点为24℃,改性后原油重复加热5次后凝点无变化,稳定性良好,为安全经济地管输高含蜡原油提供了技术支持。     

Nanohybrid polymer prepared by successive polymerization of methacrylate monomer containing silver nanoparticles in situ prepared under microwave irradiation

The well-dispersed silver nanoparticles were prepared in reactive methacrylate monomers under microwave irradiation without polymerization. In contrast to conventional heating, the synthesis of Ag nanoparticles proceeded uniformly throughout the reaction vessel only under microwave irradiation, reaching the completion of the reaction simultaneously in the whole reaction solution. Successive polymerization of the monomer containing the resulting nanoparticles has successfully produced a monohybrid of the silver nanoparticles dispersed in polymer matrix.     

Nanostructured V2O5 and its nanohybrid with MXene as an efficient electrode material for electrochemical capacitor applications

Vanadium pentoxide (V₂O₅) is an excellent electrode material for electrochemical capacitor (ECCs) applications, but its lower electrical conductivity is the primary obstacle that restricts its practical applications. This obstacle can be eliminated by forming its nanohybrid (NCs) with a highly capacitive and conductive matrix such as MXene. MXene is a new two-dimensional (2D) material with good electronic conductivity and a larger specific surface area, making it a very suitable substrate for composite formation. Unfortunately, the two-dimensional MXene sheets stacked quickly, limiting their specific surface area and charge/mass transport properties. Here we used the hydrothermal approach to fabricate V₂O₅ nanowires (NWs) and form their nanohybrid with MXene via the ultrasound route. To assess electrochemical suitability, the fabricated samples were loaded onto a carbon cloth (CC) and used as a working electrode in the half-cell configuration. The nanohybrid (V₂O₅/MXene) sample showed a good specific capacity (C_sp) of 768 F/g (at 1 A/g) because of its greater surface area, hybrid composition, excellent electrical conductivity, and passive nanostructure. It also showed superior cyclic, electrochemical and mechanical capability and maintained a specific capacity of 93.3%, even after completion of 6000 GCD tests. In addition, the nanohybrid sample electrode also exhibits superb rate performance and lost only 14.4% of its initial specific capacity on increasing the applied current density from 1 to 5 A/g. There is no doubt that V₂O₅ NWs inter-stack between MXene nanosheets to develop effective interface interaction and suppress their stacking.     

High performance graphene oxide/NiAl2O4 directly grown on carbon cloth hybrid for oxygen evolution reaction

Due to the lethargic kinetics, the oxygen evolution reaction (OER) requires a high anodic voltage, restricting the efficiency as well as practical applications for electrochemical water splitting. For this purpose, metal oxides (M ? O) are viewed as a potential competitor in this search because of their high redox potential. Still, their low conductivity and instability are two significant barriers that must be addressed. In this study the nanocomposite of NiAl₂O₄ with graphene oxide (GO) as a highly effective and long-lasting electrocatalyst for OER has been fabricated. In an alkaline (1.0 M KOH) medium, the GO/NiAl₂O₄ responds to a very sharp overpotential of 219 mV at a current density of 10 mA/cm² and with a lower value of tafel slope (43 mV/dec) as compared to its counterparts. The GO/NiAl₂O₄ corresponds to the high stability of 18 h with retained crystal structure and morphology. For the expected prolonged OER process, we assume the active redox couple due to the presence of Ni^+2/+3 metal in NiAl₂O₄ varies periodically. Furthermore, the synergistic effect of NiAl₂O₄, combined with the GO, facilitates the dynamics of O₂ evolution as a final product, and are useful for further applications in future era.     

Shear enhanced interfacial interaction between carbon nanotubes and polyethylene and formation of nanohybrid shish-kebabs

In this work, raw multiwalled carbon nanotubes (MWNTs) without any pre-treatment were blended with linear low density polyethylene (LLDPE), then molded via a so-called Dynamic Packing Injection Molding (DPIM) technique, in which oscillatory shear was exerted on the prepared composites during the stage of cooling solidification. The injection molded samples were extracted by xylene to remove LLDPE, and the remained MWNTs were collected and characterized. Shear enhanced interfacial adhesion between MWNTs and LLDPE was confirmed by dissolution experiment and Fourier transform infrared. The former a longer mixing time in xylene for remained MWNTs compared with raw MWNTs, while in the latter an increased intensity of characteristic LLDPE peak for MWNTs subjected to dynamic packing injection molding. More importantly, SEM images showed a formation of MWNTs/LLDPE nanohybrid shish-kebab, in which MWNTs served as shish, and LLDPE lamellae as kebab and periodically decorated on MWNTs. A simultaneously improved tensile strength and elongation of LLDPE have been achieved by adding the LLDPE-decorated MWNTs. Our work provides a new way for the modification of MWNTs, particularly a convenient way for the enhancement of interfacial adhesion in polymer/MWNT composites via realistic molding processing.     

3,4-Dichlorophenoxyacetate interleaved into anionic clay for controlled release formulation of a new environmentally friendly agrochemical

A new layered organic–inorganic nanohybrid material, zinc-aluminum-3,4-dicholorophenoxyacetate (N3,4-D) in which an agrochemical, 3,4-dichlorophenoxyacetic acid (3,4-D), is intercalated into zinc-aluminum-layered double hydroxide (ZAL), was synthesized by coprecipitation method. A well-ordered nanomaterial was formed with a percentage loading of 53.5% (w/w). Due to the inclusion of 3,4-D, basal spacing expanded from 8.9 Å in ZAL to 18.7 Å in N3,4-D. The Fourier transform infrared study shows that the absorption bands of the resulting nanohybrid composed of both the 3,4-D and ZAL further confirmed the intercalation episode. Thermal analysis shows that ZAL host enhances the thermal stability of 3,4-D. Controlled-release experiment shows that the release of 3,4-D in the aqueous media is in the order of phosphate > carbonate > sulfate > chloride. These studies demonstrate the successful intercalation of the 3,4-D and its controlled release property in various aqueous media.     

Graphene supported bimetallic G–Co–Pt nanohybrid catalyst for enhanced and cost effective hydrogen generation

A highly active and stable bimetallic nano-hybrid catalyst Graphene–Cobalt–Platinum (G–Co–Pt) is proposed for the enhanced and cost effective generation of hydrogen from Sodium Borohydride. Three different nano-hybrid catalysts namely Graphene–Cobalt (G–Co), Graphene–Platinum (G–Pt) and Graphene–Cobalt–Platinum (G–Co–Pt) are synthesized, characterized using XRD, FTIR, SEM, HRTEM, EDAX and Cyclic voltammetry (CV) analysis and tested for hydrogen generation. The activity and stability of the catalysts are analyzed by estimating the turnover frequency (TOF), the electrochemically active surface area (ECSA), the percentage decay of current density over ten cycles of CV and the decay in the rate of hydrogen generation with the age of catalyst. Among the three catalysts G–Co–Pt exhibits the highest catalytic activity (TOF = 107 min⁻¹, ECSA = 75.32 m²/gm) and stability. The evaluated value of activation energy of the catalytic hydrolysis using G–Co–Pt is 16 ± 2 kJ mol⁻¹.