Jiu-Ju Feng

One-pot synthesis of porous Pt–Au nanodendrites supported on reduced graphene oxide nanosheets toward catalytic reduction of 4-nitrophenol

In this work, a facile, convenient and effective one-pot wet-chemical method was developed for preparation of well-dispersed porous bimetallic Pt–Au alloyed nanodendrites uniformly supported on reduced graphene oxide nanosheets (Pt–Au pNDs/RGOs) at room temperature. The fabrication strategy was efficient and green owing to the use of cytosine as a structure-directing agent and weak stabilizing agent, without employing any organic solvent, template, seed, surfactant, or complicated apparatus. The as-synthesized Pt–Au pNDs/RGOs exhibited significantly enhanced catalytic performance toward the reduction of 4-nitrophenol, as compared to commercial Pt black and home-made Au nanocrystals.

Facile synthesis of oxygen and sulfur co-doped graphitic carbon nitride fluorescent quantum dots and their application for mercury( ii ) detection and bioimaging

In this work, uniform oxygen and sulfur co-doped graphitic carbon nitride quantum dots (OS-GCNQDs) have been prepared by thermal treatment of citric acid and thiourea. The as-obtained OS-GCNQDs show strong blue photoluminescence (PL) with a relatively high quantum yield of 14.5%. Furthermore, OS-GCNQDs exhibit stable and specific concentration-dependent PL intensities in the presence of mercury(II) ions in the range of 0.001–20.0 μM, with a detection limit of 0.37 nM (3S/N). More importantly, OS-GCNQDs were explored for cell imaging with satisfactory biocompatibility, and so are a potential fluorescent probe in biosensing and bioimaging applications.

Facile synthesis of N, S-codoped fluorescent carbon nanodots for fluorescent resonance energy transfer recognition of methotrexate with high sensitivity and selectivity

In this report, N, S-codoped fluorescent carbon nanodots (NSCDs) were prepared by a facile, simple, low-cost, and green thermal treatment of ammonium persulfate, glucose, and ethylenediamine. The as-prepared NSCDs displayed bright blue emission with a relatively high fluorescent quantum yield of 21.6%, good water solubility, uniform morphology, and excellent chemical stability, compared to pure CDs. The fluorescence of NSCDs can be significantly quenched by methotrexate (MTX) via fluorescence resonance energy transfer (FRET) between NSCDs and MTX, which was used for highly selective and sensitive detection of MTX with a wide linear range up to 50.0 μM and a low detection limit of 0.33 nM (S/N = 3). Moreover, this method was explored for practical detection of MTX in human serum with satisfied results.

A general strategy for the facile synthesis of AuM (M = Pt/Pd) alloyed flowerlike-assembly nanochains for enhanced oxygen reduction reaction

In this work, a general strategy was developed for the facile synthesis of bimetallic AuM (M = Pt or Pd) alloyed flowerlike-assembly nanochains (FANs) with the assistance of diprophylline as a structure-directing and stabilizing agent. The morphologies, crystal structures, and compositions of AuPt and AuPd FANs were investigated primarily by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The formation mechanism was discussed in some detail by varying the concentration of diprophylline. The as-prepared AuM FANs displayed improved catalytic activities and better stabilities for oxygen reduction reaction (ORR) compared to commercial E-TEK Pt/C, Pt black and Pd black.

Novel phenol biosensor based on laccase immobilized on reduced graphene oxide supported palladium-copper alloyed nanocages.

Developing new nanomaterials is of key importance to improve the analytical performances of electrochemical biosensors. In this work, palladium-copper alloyed nanocages supported on reduced graphene oxide (RGO-PdCu NCs) were facilely prepared by a simple one-pot solvothermal method. A novel phenol biosensor based on laccase has been constructed for rapid detection of catachol, using RGO-PdCu NCs as electrode material. The as-developed phenol biosensor greatly enhanced the electrochemical signals for catechol. Under the optimal conditions, the biosensor has two linear ranges from 0.005 to 1.155 mM and 1.655 to 5.155 mM for catachol detection at 0.6 V, the sensitivity of 12.65 µA mM(-1) and 5.51 µA mM(-1), respectively. This biosensor showed high selectivity, low detection limit, good reproducibility, and high anti-interference ability.

Surfactant-free synthesis of reduced graphene oxide supported porous PtAu alloyed nanoflowers with improved catalytic activity

A simple and facile one-pot wet-chemical co-reduction method was developed for the synthesis of reduced graphene oxide supported porous PtAu alloyed nanoflowers (PtAu-nanoflowers/rGO). p-Aminopyridine was employed as a structure-directing agent and a stabilizing agent. No seed, template, surfactant, or polymer was involved in the synthesis process. It was found that the reaction temperature and the dosage of p-aminopyridine were essential for the final product. Furthermore, the as-prepared nanocomposites showed improved catalytic activity for the reduction of 4-nitrophenol in contrast to monometallic Pt nanocrystals/rGO, Au nanocrystals/rGO, and commercial Pt/C (50 wt%).

Dendrite-like PtAg alloyed nanocrystals: Highly active and durable advanced electrocatalysts for oxygen reduction and ethylene glycol oxidation reactions

In this work, well-defined dendrite-like PtAg alloyed nanocrystals were prepared by a facile one-pot l-hydroxyproline-assisted successive coreduction approach on a large scale, where no any template or seed involved. l-Hydroxyproline was employed as a green structuring director. The formation mechanism of the alloyed dendritic nanocrystals was investigated in details. The as-prepared frameworks exhibited boosted electrocatalytic activity, improved stability and enhanced tolerance toward oxygen reduction reaction (ORR) and ethylene glycol oxidation reaction (EGOR) in alkaline media in contrast with commercial Pt black catalyst. The developed method provides novel strategy for preparing other shape-controlled nanocatalysts with superior catalytic activity and durability.

Green-assembly of three-dimensional porous graphene hydrogels for efficient removal of organic dyes

Herein, a facile and straightforward green-assembly approach was developed for preparation of nitrogen and sulphur co-doped three-dimensional (3D) graphene hydrogels (N/S-GHs) with the assistance of glutathione. Specifically, graphene oxide is reduced and assembled into 3D porous nanostructures with glutathione as the reducing agent and modifier for its intrinsic structure, along with the nitrogen and sulphur sources in the synthetic process. As expected, the as-obtained N/S-GHs demonstrated superior adsorption performances for organic dyes (e.g., methylene blue, malachite green, and crystal violet) in aqueous media. This work provides new insight for the green-assembly of 3D porous nanomaterials as adsorbent and their promising applications in water treatment.

One-pot solvothermal synthesis of bimetallic yolk–shell Ni@PtNi nanocrystals supported on reduced graphene oxide and their excellent catalytic properties for p-nitrophenol reduction

Well-defined bimetallic yolk–shell nanostructures of Ni@PtNi nanocrystals with porous shells were uniformly deposited on reduced graphene oxide (Ni@PtNi NCs-rGO) under hydrothermal conditions. The physical characterization was systematically investigated by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The as-fabricated products exhibited improved catalytic performance toward the reduction of p-nitrophenol in comparison with commercial Pt/C (50 wt%), monometallic Pt nanoparticles/rGO and Ni nanoparticles/rGO catalysts.

Simple one-pot synthesis of solid-core@porous-shell alloyed PtAg nanocrystals for the superior catalytic activity toward hydrogen evolution and glycerol oxidation

In this work, solid-core@porous-shell alloyed PtAg nanocrystals (PtAg NCs) were fabricated via a simple one-pot co-reduction wet-chemical method on a large scale. Diprophylline (DPP) was employed as the stabilizing agent and shape-directing agent, without any surfactant, polymer, seed or template. The products were mainly analyzed by a series of characterization technique. The hierarchical architectures had enhanced stability and improved electrocatalytic activity for hydrogen evolution reaction (HER) and glycerol oxidation reaction (GOR) in contrast with commercial available Pt/C and Pt black catalysts. For the prepared PtAg NCs catalyst, the Tafel slope is 40mVdec-1 toward HER in 0.5M H2SO4, coupled with the specific activity and mass activity of 77.91mAcm-2 and 1303mAmg-1Pt toward GOR, respectively.