- Binuclear cobalt phthalocyanine supported on manganese octahedral molecular sieve: High-efficiency catalyzer of peroxymonosulfate decomposition for degrading propranolol. [Journal Article]
- STSci Total Environ 2019 May 31; 686:97-106
- Propranolol (PRO) is widely detected in the aquatic environment and proved to be detrimental to multifarious aquatic organisms. In view of some virtues of sulfate radicals than hydroxyl radicals, adv…
Propranolol (PRO) is widely detected in the aquatic environment and proved to be detrimental to multifarious aquatic organisms. In view of some virtues of sulfate radicals than hydroxyl radicals, advanced oxidation technologies that involve the activation of peroxymonosulfate (PMS) have stimulated wide-ranging research on the PRO removal. In this paper, a composite (C2NOMS-2) of amino-functionalized manganese octahedral molecular sieve (NOMS-2) and binuclear cobalt phthalocyanine (Co2CPc) was synthesized easily, and utilized as a catalyzer for PMS to degrade PRO in water. The apparent rate constants of PRO degradation by PMS with C2NOMS-2 as a catalyst was found to be higher than with NOMS-2, Co2CPc and the composite of uninuclear cobalt phthalocyanine (CoCPc) and NOMS-2. The catalytic ability of C2NOMS-2 was investigated under various reaction conditions: catalyst dosages (0.5-2.0 g/L), PMS doses (50-500 mg/L), initial pH (5-11), reaction temperature (20-35 °C), and natural water constituents (Cl-, HCO3-, and sodium huminate). Radical scavenging tests and electron paramagnetic resonance spectroscopy showed that 1O2 was the most critical reactive oxygen species, and conceivable mechanisms of PMS activation with C2NOMS-2 were proposed established on the curve estimation of high-resolution XPS spectra, revealing that the generation of reactive oxygen species was mainly resulted from the cycles of Mn3+/Mn4+, Co3+/Co2+ and surface lattice oxygen/surface adsorbed oxygen. The intermediate products of propranolol degradation were identified by LC-MS/MS. Cycling experiments and ion dissolution detection suggested that C2NOMS-2 could maintain satisfactory stability in an aqueous system.
- Enhanced decolorization of methyl orange by Bacillus sp. strain with magnetic humic acid nanoparticles under high salt conditions. [Journal Article]
- BTBioresour Technol 2019; 288:121535
- In this study, magnetic humic acid (MHA) nanoparticle was prepared and confirmed the enhancement on reduction of azo dyes under high salt concentration. The anaerobic growth of the strain Bacillus sp…
In this study, magnetic humic acid (MHA) nanoparticle was prepared and confirmed the enhancement on reduction of azo dyes under high salt concentration. The anaerobic growth of the strain Bacillus sp. on quinones makes the biogenic hydroquinone feasible, and the latter was proven to reduce the azo dyes stoichiometrically. This in-situ reversibly oxidation and reduction of MHA acts as electron shuttle to catalyze the biotic reduction of the azo dyes. The biodegradation efficiencies in batch experiments and sequencing batch reactor with MHA were increased by 1.5-2.5 times as compared to that of control without the catalyzer. Moreover, the negligible leaching of HA under various environmental conditions suggests the robustness of the coating of HA on Fe/O surface. These results indicated that the as-prepared MHA could be used as redox mediator to accelerate the extracellular electron transfer, which is of great environmental significance for the removal of hazardous compounds.
- Thiol-click photochemistry for surface functionalization applied to optical biosensing. [Journal Article]
- ACAnal Chim Acta 2019 Jul 04; 1060:103-113
- In the field of biosensing, suitable procedures for efficient probes immobilization are of outmost importance. Here we present different light-based strategies to promote the covalent attachment of t…
In the field of biosensing, suitable procedures for efficient probes immobilization are of outmost importance. Here we present different light-based strategies to promote the covalent attachment of thiolated capture probes (oligonucleotides and proteins) on different materials and working formats. One strategy employs epoxylated surfaces and uses the light to accomplish the ring opening by a thiol moiety present in a probe. However, most of this work lies on the use of thiol-ene photocoupling chemistry to covalently attach probes to the supports. And thus, both alkenyl and thiol derivatized surfaces are assayed to immobilize thiol or alkene ended probes, respectively, and their performances are compared. Also, the effect of the number of thiols carried by the probe is analyzed comparing single-point and multi-point attachment. The performance of the analogous tethering, but onto alkynylated surfaces is also carried out, and the sensing response is related to the surfaces hydrophobicity. A newly developed reaction is also discussed where a fluorinated surface undergoes the covalent immobilization of thiolated probes activated by light, creating small hydrophilic areas where the probes are attached, and leaving the rest of the surface highly hydrophobic and repellent against protein unspecific adsorption. These mixed surfaces confine the sample (aqueous) uniquely on the hydrophilic spots lowering the background signal and thus increasing the sensitivity. These probe immobilization approaches are applied to fluorescence microarray and label-free nanophotonic biosensing. All the exposed reactions have in common the photoactivation of the thiol moieties, and give rise to quick, clean, versatile, orthogonal and biocompatible reactions. Water is the only solvent used, and light the only catalyzer applied. Thus, all of them can be considered as having the attributes of click-chemistry reactions. For these reasons we named them as thiol-click photochemistry, being a very interesting pool of possibilities when building a biosensor.
- Construction of an ultrasensitive electrochemiluminescent aptasensor for ractopamine detection. [Journal Article]
- AAnalyst 2019 Apr 08; 144(8):2550-2555
- In this study, an ultrasensitive electrochemiluminescence (ECL) aptasensor based on Ru(bpy)32+-doped silica nanoparticles (Ru@SiO2 NPs) coupled with gold nanoparticles (Au NPs) was developed for the …
In this study, an ultrasensitive electrochemiluminescence (ECL) aptasensor based on Ru(bpy)32+-doped silica nanoparticles (Ru@SiO2 NPs) coupled with gold nanoparticles (Au NPs) was developed for the determination of ractopamine (Rac). TPrA is used as the coreactant, the Ru@SiO2 NPs serve as the ECL luminophores, and the Au NPs work as a catalyzer in the redox reaction as well as the carrier that immobilizes the aptamer. Meanwhile, the complete incorporation of the Ru@SiO2 NPs and Au NPs increases the localized surface plasmon resonance (LSPR) probability, thus promoting ECL emission. The ractopamine (Rac) target molecules are specifically captured on the electrode surface by aptamer recognition. The ECL signal is quenched by energy transfer from the luminophore to benzoquinone compounds, which are oxidative products of Rac from the electrochemical scanning process. The proposed ECL aptasensor exhibits ultrahigh sensitivity and excellent selectivity for Rac detection. The linear response ranged over Rac concentrations from 1.5 × 10-12 M to 1.5 × 10-8 M with a detection limit of 4.1 × 10-14 M (S/N = 3). The detection recovery of Rac in real meat samples confirmed the satisfactory performance of the method. This study describes a versatile ECL aptasensor based on the combined functions of luminous nanospheres and Au NPs, indicating its potential application for the ultrasensitive analysis of targets in diverse systems.
- Photoelectrochemical platform for MicroRNA let-7a detection based on graphdiyne loaded with AuNPs modified electrode coupled with alkaline phosphatase. [Journal Article]
- BBBiosens Bioelectron 2019 Apr 01; 130:269-275
- In this work, a photoactive material, Graphdiyne (GDY) loaded with AuNPs (AuNPs-GDY), was successfully synthesized. The fabricated material made use of the natural band-gap structure of GDY, which co…
In this work, a photoactive material, Graphdiyne (GDY) loaded with AuNPs (AuNPs-GDY), was successfully synthesized. The fabricated material made use of the natural band-gap structure of GDY, which could produce hole-electron pairs and the plasmon resonance effect of AuNPs to obtain a high photoelectrochemical (PEC) response. AuNPs-GDY PEC response changed with the mass ratio of GDY to tetrachloroauric acid. When the mass ratio of GDY to tetrachloroauric acid was 1:2.5, AuNPs-GDY exhibited the best PEC performance. Thus, the best one was selected as the photoactive material to establish a PEC biosensor for microRNA detection. The PEC biosensor used the alkaline phosphatases as catalyzer to generate ascorbic acid in situ, which provided a low background signal and a high PEC response. The cancer marker, MicroRNA let-7a, was chosen as a target model. Under optimal condition, potential 300 mV and pH 8.0, the PEC biosensor had a detection limit of 3.3 × 10-19 M and a good linearity with microRNA let-7a concentration ranged from 1.0 × 10-18 M to 1.0 × 10-10 M. This PEC biosensor opened a promising platform using GDY to fabricate analytical method and detect microRNA at ultralow levels for diagnoses.
- Catalytic Performance of Nitrogen-Doped Activated Carbon Supported Pd Catalyst for Hydrodechlorination of 2,4-Dichlorophenol or Chloropentafluoroethane. [Journal Article]
- MMolecules 2019 Feb 14; 24(4)
- Nitrogen-doped activated carbon (N-AC) obtained through the thermal treatment of a mixture of HNO₃-pretreated activated carbon (AC) and urea under N₂ atmosphere at 600 °C was used as the carrier of P…
Nitrogen-doped activated carbon (N-AC) obtained through the thermal treatment of a mixture of HNO₃-pretreated activated carbon (AC) and urea under N₂ atmosphere at 600 °C was used as the carrier of Pd catalyst for both liquid-phase hydrodechlorination of 2,4-dichlorophenol (2,4-DCP) and gas-phase hydrodechlorination of chloropentafluoroethane (R-115). The effects of nitrogen doping on the dispersion and stability of Pd, atomic ratio of Pd/Pd2+ on the surface of the catalyzer, the catalyst's hydrodechlorination activity, as well as the stability of N species in two different reaction systems were investigated. Our results suggest that, despite no improvement in the dispersion of Pd, nitrogen doping may significantly raise the atomic ratio of Pd/Pd2+ on the catalyst surface, with a value of 1.2 on Pd/AC but 2.2 on Pd/N-AC. Three types of N species, namely graphitic, pyridinic, and pyrrolic nitrogen, were observed on the surface of Pd/N-AC, and graphitic nitrogen was stable in both liquid-phase hydrodechlorination of 2,4-DCP and gas-phase hydrodechlorination of R-115, with pyridinic and pyrrolic nitrogen being unstable during gas-phase hydrodechlorination of R-115. As a result, the average size of Pd nanocrystals on Pd/N-AC was almost kept unchanged after liquid-phase hydrodechlorination of 2,4-DCP, whereas crystal growth of Pd was clearly observed on Pd/N-AC after gas-phase hydrodechlorination of R-115. The activity test revealed that Pd/N-AC exhibited a much better performance than Pd/AC in liquid-phase hydrodechlorination of 2,4-DCP, probably due to the enhanced stability of Pd exposed to the environment resulting from nitrogen doping as suggested by the higher atomic ratio of Pd/Pd2+ on the catalyst surface. In the gas-phase hydrodechlorination of R-115, however, a more rapid deactivation phenomenon occurred on Pd/N-AC than on Pd/AC despite a higher activity initially observed on Pd/N-AC, hinting that the stability of pyridinic and pyrrolic nitrogen plays an important role in the determination of catalytic performance of Pd/N-AC.
- Catalyst-Assisted Solution-Liquid-Solid Synthesis of CdS/CuInSe2 and CuInTe2/CuInSe2 Nanorod Heterostructures. [Journal Article]
- ICInorg Chem 2019 Jan 07; 58(1):695-702
- Axial nanowire heterostructures composed of cadmium sulfide (CdS)/copper indium diselenide (CuInSe2) and copper indium telluride (CuInTe2)/copper indium diselenide (CuInSe2) were synthesized by a sol…
Axial nanowire heterostructures composed of cadmium sulfide (CdS)/copper indium diselenide (CuInSe2) and copper indium telluride (CuInTe2)/copper indium diselenide (CuInSe2) were synthesized by a solution-liquid-solid (SLS) method with the catalyzer of bismuth nanocrystals. Electron microscopy and diffraction studies show CuInTe2 and CuInSe2 segments growing along the  direction with a clear epitaxial interface between them. In CdS/CuInSe2 nanorod heterostructures, CuInSe2 and CdS segments grow along the  and  direction, respectively, with an obvious epitaxial interface between them. Energy-dispersive X-ray spectrometry demonstrates the alloy-free composition modulation in two nanorod heterostructures. In CuInTe2/CuInSe2 nanorod heterostructures, Te and Se are localized in CuInTe2 and CuInSe2 segments, respectively. Cu/In/Se and Cd/S are localized in the CuInSe2 and CdS sections of the CdS/CuInSe2 nanorod heterostructures. This research confirms that the SLS mechanism provides a general alternate technique to prepare multicomponent axial 1D heterostructures that have been difficult to generate by using either catalyst-free solution-phase synthesis or vapor-liquid-solid growth.
- Fabrication of Uniform Gold Nanopatterns on Graphene by Using Nanosphere Lithography. [Journal Article]
- JNJ Nanosci Nanotechnol 2019 May 01; 19(5):2851-2855
- In this study, we have realized controllable fabrication of gold nanopatterns on pristine monolayer graphene by using nanosphere lithography, in which polystyrene (PS) spheres are used as templates. …
In this study, we have realized controllable fabrication of gold nanopatterns on pristine monolayer graphene by using nanosphere lithography, in which polystyrene (PS) spheres are used as templates. With this method, periodically ordered triangular Au nanopatterns are uniformly formed on graphene surface. Micro-Raman spectroscopy shows that these sacrificial PS templates have no obvious effect on graphene surface structure while the subsequently formed Au nanopatterns are found to enhance Raman intensity of G and 2D bands by surface plasmon resonance. The compressive stress introduced in the metal deposition process leads to an obvious blue shift of 2D band. Besides, the metal-induced doping effect reduces the intensity ratio between 2D and G bands. This uniform arrangement of metal nanostructure is expected to grow other nanomaterials or used as Raman enhancement substrate in biomedicine, catalyzer and optics areas.
- Alkaline Hydrothermal Synthesis, Characterization, and Photocatalytic Activity of TiO₂ Nanostructures: The Effect of Initial TiO₂ Phase. [Journal Article]
- JNJ Nanosci Nanotechnol 2019 Mar 01; 19(3):1511-1519
- One-dimensional (1D) titanate nanostructures were synthesized by hydrothermal route, using commercially available TiO₂ (P25) and anatase powders as precursor materials and strong NaOH solution as cat…
One-dimensional (1D) titanate nanostructures were synthesized by hydrothermal route, using commercially available TiO₂ (P25) and anatase powders as precursor materials and strong NaOH solution as catalyzer. The prepared titanates were calcined, followed by protonation to produce TiO₂ nanostructures having enhanced photocatalytic and photovoltaic properties. The synthesized TiO₂ 1D nanostructures were characterized using field-emission scanning electron microscope, high-resolution electron microscope, X-ray diffraction analysis, and UV-Vis photospectroscopy to understand the effect of initial TiO₂ phase on morphological and crystallographic features, and bandgap. Methylene blue degradation test was applied to evaluate the photoactivity of the products obtained after different stages of the process. The findings indicate that 1D TiO₂ nanostructures form by different mechanisms from dissolved aggregates during hydrothermal process, depending on the crystal structure of the initial precursor used. Photocatalytic test results reveal that protonated titanates have considerable adsorption capability, while photocatalytic degradation depends on TiO₂ transformation.
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- Cooperative Action for Molecular Debromination Reaction on Cu(110). [Journal Article]
- JAJ Am Chem Soc 2018 Nov 21; 140(46):15631-15634
- Copper is the paradigmatic catalyzer of the Ullmann cross-coupling reaction. Despite this, its role in the reaction is still under debate. Here, we shed light on the mechanistic steps of debrominatio…
Copper is the paradigmatic catalyzer of the Ullmann cross-coupling reaction. Despite this, its role in the reaction is still under debate. Here, we shed light on the mechanistic steps of debromination, characterizing a prototypical molecule, namely 4,7-dibromobenzo[ c]-1,2,5-thiadiazole (2Br-BTD), deposited on a Cu(110) surface. By means of scanning probe techniques and first principle calculations, we demonstrate the oxidative addition of Cu atoms leading to a -C-Cu-Br metal-organic complex. The scission of the strongly bound bromine atoms requires the cooperative action of neighboring complexes resulting in the formation of Cu-coordinated BTD structures.