One inorganic-organic hybrid derived from reduced molybdophosphate and trinuclear cadmium(Ⅱ) fragment

One new polyoxometalate (POM)-based inorganic-organic hybrid [Cd3Ⅱ(HPO4)(Hbpp)(H2O)2]{CdⅡ[P4- Mo6O28H3.5(OH)3]2} (H4tpb)·7H2O (1) (bpp = 1,3-bis-(4-pyridyl)propane, tpb = 1,2,4,5-tetra(4-pyridyl)-benzene) constructed from reduced molybdophosphate [P4Mo6O28H3.5(OH)3]5.5- (P4Mo6), trinuclear CdⅡ-phosphate-Hbpp fragment and protonated tpb has been hydrothermally synthesized and structurally characterized by IR, elemental analyses and single crystal X-ray diffraction. The complex 1 crystallizes in the monoclinic system with the space group P21/c and cell parameters of a = 15.672(12)Å, b = 23.839(19)Å, c = 27.654(2)Å, β = 115.850(10)8, V = 9297.9(12) Å3, Z = 4, R1 = 0.0534 and wR2 = 0.1135. In complex 1, the P4Mo6 units are bridged by CdⅡ ions to form the classic sandwich-type [Cd(P4Mo6)2] dimers, which are further connected into a two dimensional network via the trinuclear CdⅡ subunits. The tpb is synthesized in situ from the bpp ligands and connects the adjacent 2D layers into a 3D supramolecular framework through hydrogen bonding interactions. The electrochemical and fluorescent properties of complex 1 have been investigated.     

Simultaneous Voltammetric Determination of Captopril and Hydrochlorothiazide on a Graphene/Ferrocene Composite Carbon Paste Electrode

In this work, a voltammetric method has been developed for the simultaneous determination of captopril (CPT) and hydrochlorothiazide (HCT) in pharmaceutical combinations and clinical samples using a graphene/ferrocene composite carbon paste (GR/Fc/CP) electrode. The electrochemical behaviors of CPT and HCT were individually and simultaneously investigated at the surface of the GR/Fc/CP electrode. In differential pulse voltammetric (DPV) mode and under optimized experimental conditions, CPT and HCT gave linear responses over the concentration ranges 1.0–430 µM and 0.5–390 µM (r²>0.99), respectively. The prepared electrode could be used for simultaneous determination of CPT and HCT in some real samples.     

Electrodeposition of PdAu Alloy Nanoparticles on Ionic Liquid Functionalized Graphene Film for the Voltammetric Determination of Oxalic Acid

An ionic liquid functionalized graphene film was prepared and PdAu nanoparticles (NPs) were electrodeposited on it. The PdAu NPs were characterized by various methods and they showed the features of alloys. In 0.2 M H₂SO₄ solution, oxalic acid (OA) exhibited a sensitive anodic peak at the resulting electrode at about 1.1 V (vs. SCE), and the peak current was linear to OA concentration in the range of 5–100 µM with a sensitivity of 45.5 µA/mM. The detection limit was 2.7 µM (S/N=3). The electrode was successfully applied to the determination of OA in real sample.     

Sensitive Stripping Determination of Cadmium(II) and Lead(II) on Disposable Graphene Modified Screen‐Printed Electrode

In the present work, a sensitive, facile and disposable sensing platform for trace analysis of heavy metal ions was developed at the Bi modified graphene‐poly(sodium 4‐styrenesulfonate) composite film screen printed electrode (GR/PSS/Bi/SPE). The GR/PSS/Bi/SPE improved sensitivity and linearity due to the functionalization of graphene with negatively charged PSS providing more absorbing sites. The detection limit of the GR/PSS/Bi/SPE is found to be 0.042 µg L^?1 for Cd²⁺ and 0.089 µg L^?1 for Pb²⁺ with linear responses of Cd²⁺ and Pb²⁺ in the range of 0.5–120 µg L^?1. Finally, the practical application was confirmed in real water with satisfactory results.     

Fabrication of an Electrochemical L‐Cysteine Sensor Based on Graphene Nanosheets Decorated Manganese Oxide Nanocomposite Modified Glassy Carbon Electrode

The graphene nanosheets/manganese oxide nanoparticles modified glassy carbon electrode (GC/GNSs/MnOx) was simply prepared by casting a thin film of GNSs on the GC electrode surface, followed by performing electrodeposition of MnOx at applied constant potential. The GC/GNSs/MnOx modified electrode shows high catalytic activity toward oxidation of L ‐cysteine. Hydrodynamic amperometry determination of L ‐cysteine gave linear responses over a concentration range up to 120 µM with a detection limit of 75 nM and sensitivity of 27 nA µM^?1. The GC/GNSs/MnOx electrode appears to be a highly efficient platform for the development of sensitive, stable and reproducible L ‐cysteine electrochemical sensors.     

Graphene‐based solid‐phase extraction disk for fast separation and preconcentration of trace polycyclic aromatic hydrocarbons from environmental water samples

Graphene has great potentials for the use in sample preparation due to its ultra high specific surface area, superior chemical stability, and excellent thermal stability. In our work, a novel graphene‐based SPE disk was developed for separation and preconcentration of trace polycyclic aromatic hydrocarbons from environmental water samples. Based on the strong π–π stacking interaction between the analytes and graphene, the analytes extracted by graphene were eluted by cyclohexane and then determined by GC‐MS. Under the optimized conditions, high flow rate (30 mL/min) and sensitivity (0.84–13 ng/L) were achieved. The proposed method was successfully applied to the analysis of real environmental water samples with recoveries ranging from 72.8 to 106.2%. Furthermore, the property of anticlogging and reusability was also improved. This work reveals great potentials of graphene‐based SPE disk in environmental analytical.     

Graphene grafted silica‐coated Fe3O4 nanocomposite as absorbent for enrichment of carbamates from cucumbers and pears prior to HPLC

In this paper, a novel graphene (G) grafted silica‐coated Fe₃O₄ nanocomposite was fabricated by the chemical bonding of G onto the surface of silica‐coated Fe₃O₄ nanoparticles. Some carbamates (metolcarb, carbaryl, pirimicarb, and diethofencarb) in cucumber and pear samples were enriched by this nanocomposite prior to their determination by HPLC with UV detection. Experimental parameters that may affect the extraction efficiency were investigated. Under the optimum conditions, a linear response was achieved in the concentration range of 0.5–100.0 ng/g for metolcarb, carbaryl, and diethofencarb, and 1.0–100 ng/g for pirimicarb with the correlation coefficients (r) ranging from 0.9956 to 0.9984. The LOD (S/N = 3) of the method were found to be in the range from 0.08 to 0.2 ng/g. The RSDs were in the range from 2.4 to 5.8%. The results indicated that the G grafted silica‐coated Fe₃O₄ nanocomposite was stable and efficient for magnetic SPE and has a great application potential for the preconcentration of other organic pollutants from real samples.     

Synthesis and properties of near IR induced self-healable polyurethane/graphene nanocomposites

A series of self-healable polyurethane (SHPU)/modified graphene (MG) nanocomposites were synthesized from poly(tetramethylene glycol) (PTMG) and 4,4′-methylene diphenyl diisocyanate (MDI) with minute amounts (0–1 wt%) of MG which was chemically modified graphene oxide (GO) with phenyl isocyanate and reduced in the presence of phenylhydrazine.     

Chromium(V) Oxide Trichloride,and some Pentachlorido‐­oxido‐chromate(V) Salts: Structures and Spectroscopic ­Characterization

Crystalline CrOCl₃ contains [Cl₂OCr(μ‐Cl)₂CrOCl₂] molecules with two square pyramidal CrOCl₄ units sharing a common edge and with the Cr–O arranged anti, a new structure type for transition metal MOX₃ compounds. Crystals are monoclinic with space group P2₁/c, Z = 4, with a = 5.735(5), b = 13.738(7), c = 11.318(4) Å, α = 90°, β = 98.346(6)°, γ = 90°. Its IR and UV/Vis spectra are reported and compared with those of the C_3v monomer found in the gas phase. Structures are also reported for M₂[CrOCl₅] (M = Cs or Rb) and show a pseudo‐octahedral anion. Cs₂[CrOCl₅] adopts a K₂PtCl₆‐type structure with [CrOCl₅]^2– ions randomly orientated, but Rb₂[CrOCl₅] is orthorhombic with space group Pnma with a = 13.6471(7), b = 9.9175(5), and c = 6.9562(4) Å. Rietveld refinement of the data on the rubidium salt gave Cr–O = 1.628(1), Cr–Cl_transO = 2.652(7), Cr–Cl_transCl = 2.239(8)–2.342(3) Å. Corresponding Cr^V oxide bromide species do not form.     

CdS/石墨烯纳米复合物的可见光催化效率和抗光腐蚀行为

制备了一系列CdS纳米晶/石墨烯(CdS/GR)复合物,并在可见光照条件下评价了其光催化降解亚甲基蓝的光催化效率和抗光腐蚀行为. 研究表明,石墨烯的引入加速了CdS纳米晶(NCs)光生电子的迁移速率,抑制了其光生电子-空穴的复合,有效改善了其光催化降解有机污染物的性能. CdS/GR复合物中的石墨烯含量显著影响其光催化效率,其中石墨烯含量为4.6%的光催化剂效率最高,其光电流是CdS NCs的2.3倍. 利用光电化学和X射线衍射技术进一步证实,石墨烯的引入抑制了CdS NCs光腐蚀的发生,提高了CdS/GR复合物的光催化稳定性.