Xiaomeng Lü

Shape-controlled synthesis of F-substituted hydroxyapatite microcrystals in the presence of Na2EDTA and citric acid.

We present a facile strategy for the shape-controlled synthesis of F-substituted hydroxyapatite (FHAp) microcrystals based upon using a combination of Na(2)EDTA and citric acid (CA). Novel, well-defined FHAp microcrystals of various shapes, such as hexagonal disks with predominant (0 0 0 1) faces, hexagonal shuttles, hexagonal prisms, icosahedrons, and hexagonal microrods with tunable aspect ratios, were fabricated. In particular, FHAp hollow microcrystals with tunable shapes were fabricated directly without using any additional template. The central features of our approach are the use of both Na(2)EDTA and CA as two distinct chelating reagents and the use of substitution ions (F(-)) itself as a growth inhibitor for the FHAp crystals. F(-) ions were found to play a critical role in the formation of hexagonally shaped FHAp microcrystals, and in the one-pot formation of hollow microcrystals, which relies on the addition order of F(-) ions in the synthesis.

Highly efficient visible-light photocatalysts: reduced graphene oxide and C3N4 nanosheets loaded with Ag nanoparticles

In the current study, the degradation of methyl orange under visible-light irradiation was performed to gain an insight into the performance of the novel Ag/C3N4/reduced graphene oxide photocatalyst (Ag/C3N4/RGO). Using N,N-dimethylformamide (DMF) as an effective reducing agent as well as solvent, Ag nanoparticles were well anchored on C3N4/RGO nanosheets, which were prepared by a facile hydrothermal reaction. Inexpensive, stable C3N4 was coupled with well-conductive RGO and the plasmon resonance effect of Ag exhibited higher activities compared with pure C3N4, C3N4/RGO, Ag/RGO, and Ag/C3N4, respectively. The presence of Ag and RGO was confirmed by FTIR, XRD, and TEM, and their influence on the activity of C3N4 was demonstrated with the photocatalytic results, detection of reactive species and mechanism analysis. The photoluminescence spectra (PL) and the transient photocurrent response were also tested to determine the enhanced separation of photogenerated charge carriers. The facile synthesis of Ag/C3N4/RGO, together with their superior catalytic performance, successfully provide a promising route for the rational design of comparatively inexpensive and highly active C3N4-based ternary nanostructured composites.

CTAB-assisted synthesis and characterization of Bi2WO6 photocatalysts grown from WO3·0.33H2O nanoplate precursors

Using WO3·0.33H2O nanoplates as precursors in cetyltrimethylammonium bromide (CTAB)-assisted processes, bismuth tungstate (Bi2WO6) nanonests and nanosheets were successfully prepared by a facile hydrothermal method, followed by characterization by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectra, nitrogen adsorption–desorption [Brunauer–Emmett–Teller (BET)] analysis, and UV–Vis diffuse reflectance spectra. The results indicated that the concentration of cetyltrimethylammonium bromide played a major role in the formation of Bi2WO6 nanonests. A possible formation mechanism is presented on the basis of the experimental results. The photocatalytic activities of the resulting Bi2WO6 nanostructures were also evaluated by photodegradation of methylene blue under visible-light irradiation. Bi2WO6 nanonests showed higher photocatalytic activity than Bi2WO6 nanosheets, because of their higher surface area and special structure.Graphical Abstract

Fabrication of noble-metal-free NiS2/g-C3N4 hybrid photocatalysts with visible light-responsive photocatalytic activities

Nanocomposites of NiS2 with graphitic carbon nitride (NiS2/g-C3N4) have been successfully synthesized by means of a facile hydrothermal method. The photocatalytic activities of as-prepared samples were evaluated by monitoring the photodecomposition of rhodamine B under visible light irradiation. The experimental results indicated that visible light-driven NiS2/g-C3N4 composites exhibited an enhanced photocatalytic activity compared to that of pure NiS2, due to the fast generation, separation and transportation of the photogenerated carriers resulting from the addition of NiS2 nanoparticles (NPs). Interestingly, different amounts of NiS2 deposition can affect the photocatalytic activities of the NiS2/g-C3N4 composites. A suitable loading amount of NiS2 NPs presents the best photodegradation performance. The photocatalytic reaction mechanism for the improved photocatalytic performance of NiS2/g-C3N4 catalyst was proposed which was supported by PL, PEC, EIS and active species trapping results. A promising strategy presented here provides a facile route towards the development of economical, noble metal-free composites as photocatalysts for the applications in environmental remediation.

Synthesis and size-dependent electrochemical nonenzymatic H2O2 sensing of cuprous oxide nanocubes

In this work, we reported an electrochemical approach for the nonenzymatic detection of H2O2 based on a cuprous oxide (Cu2O) nanocube-based sensor. The Cu2O nanocubes were synthesized with controllable sizes from 40 nm to 360 nm through a facile additive-free aqueous solution route at room temperature. The electrocatalytic activities of the Cu2O nanocubes with five different sizes towards H2O2 were systematically explored, and it was found that the electrocatalytic activity was strongly dependent on the size of the Cu2O nanocubes. The cyclic voltammetry and amperometry results show that these Cu2O nanocubes exhibited good electrocatalytic activity with a linear response ranging from 0.5 to 8.5 mM at −0.2 V and a detection limit of 1.61 μM (S/N = 3). Furthermore, the Cu2O nanocubes of five different sizes have good selectivity for H2O2 detection with ascorbic acid (AA), uric acid (UA) and glucose (Glu).

Simple preparation of CuFe2O4/C3N4 composites: characterisation and enhanced photocatalysis

Abstract Novel magnetic CuFe2O4/g-C3N4 composite photocatalysts (CFCN) have been successfully prepared via a facile hydrothermal method. The CuFe2O4/g-C3N4 composites were characterised by X-ray diffraction, Fourier transform spectrophotometer, transmission electron microscopy, high resolution transmission electron microscopy, Brunauer–Emmett–Teller, and photoluminescence spectroscopy (PL). The photocatalytic activity of the as prepared CFCN composite photocatalysts was evaluated by the degradation of RhB under visible light irradiation. The CFCN composite photocatalysts exhibited enhanced photocatalytic activity for the synergic effect of CuFe2O4 and C3N4, which can lead to electron−hole pairs separation proved by PL analysis. Furthermore, the presence of H2O2 also improved the photocatalytic activity due to the possible Fenton-like effect. Because of the magnetic properties of CFCN composites, the catalysts can magnetically be recovered from the suspension solution. Therefore, the CFCN composite is a promising photocatalytic material for the applications in pollutant removal.

A novel synthesis of P/BiPO4 nanocomposites with enhanced visible-light photocatalysis

Abstract Using red phosphorus as precursors, P/BiPO4 composites were synthesised successfully via a facile hydrothermal method by the reaction between amorphous red (P) and Bi(NO3)3 aqueous solution without any additive. The phases structures, morphologies and optical properties of the obtained samples were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FTIR), Scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), UV–Vis DRS and photoluminescence spectroscopy (PL). The P/BiPO4 composite photocatalyst displayed much higher photocatalytic performance for a typical dye pollutant methylene blue (MB) degradation than the BiPO4 synthesised by a typical method under simulated visible light (λ>400 nm) and exhibited more enhanced catalytic efficiency than BiPO4 synthesised by a typical method. The excellent performance can be attributed to the high separation capacity of photogenerated electron–hole pairs and demonstrated to be a promising photocatalytic material.

Ag-embedded MnO nanorod: facile synthesis and oxygen reduction

Using manganese(II) acetate tetrahydrate and silver salts as precursors, heterostructured Ag@Ag1.8Mn8O16 nanocomposites were obtained by in situ redox reaction at room temperature. The molar ratio of Ag+/Mn2+ was found to play an essential role in determining their morphology. At a molar ratio of 1 : 200, novel nanorod products with diameters of 10–20 nm and lengths of 280–800 nm were obtained. The nanorods were thermally unstable, with further calcination leading to pure MnO nanorods embedded with Ag as the final product, which was demonstrated by analysis of XRD, TEM, Raman spectroscopy and XPS. TG and TEM analysis were also considered to explore the influence of calcination temperature and the molar ratio on the crystalline structure and the morphology of the synthesized product. The novel nanorod exhibited improved performance in oxygen reduction reaction (ORR), indicating a cost-effective electrocatalyst.

Bis(3,5-dimethyl­pyrazole)[N-salicyl­idene-β-alaninato(2–)]copper(II) dihydrate

In the title compound, [Cu(C10H10NO3)(C5H8N2)2]·2H2O, the CuII atom is coordinated by three N atoms and two O atoms in a distorted square-pyramidal geometry. The crystal packing is stabilized by intermolecular O—H⋯O and N—H⋯O hydrogen bonds.