Shumin Li

Robust superhydrophobic TiO2@fabrics for UV shielding, self-cleaning and oil–water separation

Inspired by the surface geometry and composition of the lotus leaf with its self-cleaning behavior, in this work, a TiO2@fabric composite was prepared via a facile strategy for preparing marigold flower-like hierarchical TiO2 particles through a one-pot hydrothermal reaction on a cotton fabric surface. In addition, a robust superhydrophobic TiO2@fabric was further constructed by fluoroalkylsilane modification as a versatile platform for UV shielding, self-cleaning and oil–water separation. The results showed TiO2 particles were uniformly distributed on the fibre surface with a high coating density. In comparison with hydrophobic cotton fabric, the TiO2@fabric exhibited a high superhydrophobic activity with a contact angle of ∼160° and a sliding angle lower than 10°. The robust superhydrophobic fabric had high stability against repeated abrasion without an apparent reduction in contact angle. The as-prepared composite TiO2@fabric demonstrated good anti-UV ability. Moreover, the composite fabric demonstrated highly efficient oil–water separation due to its extreme wettability contrast (superhydrophobicity/superoleophilicity). We expect that this facile process can be readily and widely adopted for the design of multifunctional fabrics for excellent anti-UV, effective self-cleaning, efficient oil–water separation, and microfluidic management applications.

Electrochemical synthesis of gold nanoparticles decorated flower-like graphene for high sensitivity detection of nitrite

In this paper, the spherical Au nanoparticles and 3D flower-like structure graphene were successively deposited on glassy carbon electrode (GCE) (Au/f-GE/GCE) via a facile and two-step electrodeposition method for the detection of nitrite ions (NaNO2). The morphology and composition elements were confirmed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction measurements (XRD). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to evaluate the electrochemical behaviors of NaNO2 on the as-prepared electrode. Compared to f-GE/GCE and Au/GCE, Au/f-GE/GCE showed a sharp and obvious oxidation peak at 0.78V. The oxidation peak current of NaNO2 was linearly proportional to its concentration in the range from 0.125 to 20375.98μM, with a detection limit of 0.01μM (at S/N=3). Furthermore, the experiment results also showed that the as-prepared electrode exhibited excellent reproducibility and long-term stability, as well as good recovery when applied to the determination of NaNO2 in pickled pork samples.

Self-supported porous 2D AuCu triangular nanoprisms as model electrocatalysts for ethylene glycol and glycerol oxidation

Shape-controlled synthesis of self-supported metallic nanocrystals with abundant active surface areas is of vital importance for the design and fabrication of novel outstandingly excellent electrocatalysts. Motivated by this, we herein report our research in the synthesis of self-supported porous 2D AuCu triangular nanoprisms via a facile wet-chemical method. Owing to the attractive 2D triangular structure, bifunctional and electronic effects between Au and Cu, such unique Au1Cu1 nanoprisms exhibited extremely high catalytic activities towards ethylene glycol and glycerol electrooxidation with mass activities of 2873 and 2263 mA mgAu−1, which are 3.0 and 3.9-fold enhancements over those of pure Au (958 and 573 mA mgAu−1), respectively. We trust this strategy may be extended to the syntheses of other multimetallic nanocatalysts with such fascinating nanostructures and the as-obtained porous triangular nanoprisms can be well applied to serve as highly desirable anode catalysts for electrooxidation of ethylene glycol and glycerol.

Facile fabrication of novel PdRu nanoflowers as highly active catalysts for the electrooxidation of methanol

The shape-controlled synthesis of binary Pd-based nanocrystals bounded with abundant surface active areas and tunable atomic ratio have been of great significance in the fabrication and modification of outstandingly excellent electrocatalysts. To embody the superiority of high surface area in enhancing electrocatalysis well, the superior electrocatalyst should be supposed to combine both the morphology advantages and the synergistic effect between metals. We herein report our significant advances in engineering the unique binary PdRu nanoflowers with highly exposed active sites and tunable compositions. Owing to the bifuntional effect and electronic effect between Pd and Ru, as well as the unique flower-like structure, such special PdRu nanoflower exhibit outstandingly excellent catalytic activity towards methanol electrooxidation with the mass activity of 1280mAmg-1, 7.01 and 4.92-fold enhancement than that of pure Pd and commercial Pd/C. Our efforts in this work may open a new way for enhancing the catalytic activity by constructing the catalysts with desirable shape and maximizing the active surface areas.

One-pot fabrication of N-doped graphene supported dandelion-like PtRu nanocrystals as efficient and robust electrocatalysts towards formic acid oxidation

Engineering the architectures of metal nanocatalysts offers a valid approach for the development of electrocatalysts with greatly enhanced performances. Herein, we report the one-pot method to successfully fabricate the N-doped graphene (NG) supported dandelion-like PtRu nanocrystals. Such dandelion-like nanocrystals with different compositions can be readily tuned via the addition of different amounts of RuCl3. By virtue of the large accessible surface active areas, synergistic and electronic effect, as well as the successful introduction of NG, the as-obtained PtRu/NG with optimized compositions display outstandingly high electrocatalytic activity towards formic acid electrooxidation with the mass and specific activities of 1857.4mAmg-1 and 18.3mAcm-2, 6.3 and 3.3 times higher than those of commercial Pt/C, respectively. Moreover, the Pt1Ru1/NG can endure at least 500 cycles with less activity decay, showing a new class of Pt-based electrocatalysts with enhanced performance for fuel cells and beyond.

Fabrication of reduced graphene oxide–bimetallic Pd@Au nanocomposites for simultaneous determination of ascorbic acid, dopamine and uric acid

In this work, we have successfully developed a facile method for the fabrication of Pd@Au core–shell (Pd@Au) heterostructures using Pd nanocubes as the structure-directing cores. The glassy carbon electrode (GCE) modified by the Pd–Au core–shell (Pd@Au)/RGO was fabricated and employed to simultaneously determine concentrations of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Because of the synergistic effect among Au, Pd and RGO, the Pd@Au/RGO/GCE demonstrates excellent electrocatalytic activity, electron transfer capability, selectivity and sensitivity in detection of AA, DA and UA. TEM images and EDX mapping showed that the as-synthesized Pd@Au nanoparticles were in Pd core and Au shell nanostructures, distributed homogeneously on the reduced graphene oxide. Cyclic voltammetries (CVs) and differential pulse voltammetry (DPV) were used to evaluate the electrochemical behaviors of AA, UA and DA on the as-fabricated electrode. Three sharp and separate oxidation peaks were observed with the co-existence of AA, DA and UA. Good linear calibration plots for AA, DA and UA were established by simultaneously increasing the concentration of AA, DA and AA in the ranges of 50–2856.63 μM, 1–400.56 μM and 5–680.76 μM, respectively. The individual DPVs for AA, DA and UA were also investigated and detection limits estimated were 24.88 μM, 0.2 μM and 1.25 μM, respectively. Moreover, the modified electrode demonstrated high performance when it was applied to test the content of AA, DA and UA in the analysis of real samples.

Enhanced photo-electrochemical response of reduced graphene oxide and C3N4 nanosheets for rutin detection

Herein, a sensitive photo-electrochemical sensor based on C3N4 and reduced graphene oxide nanosheets modified glassy carbon electrode (C3N4-RGO/GCE) has been fabricated for the detection of rutin under UV light illumination. In C3N4-RGO catalyst, RGO not only works as a template but also promotes electron transfer, meanwhile, C3N4 acts as a photocatalyst. Benefiting from the superior electron transfer capacity and efficient UV light effect of the C3N4-RGO catalyst, we get a photo-electrochemical sensor for the rutin detecting with a low detection limit of 1.78×10-9molL-1 and an excellent linear range of 5×10-9-1.4×10-4molL-1. Meanwhile, the achieved C3N4-RGO/GCE demonstrated nice selectivity, good reproducibility as well as reliable stability. Moreover, compared with the electrochemical determination, the C3N4-RGO electrode provides a new way for rutin detection by photo-electrochemical method with a promising UV light responsive result.

Nonenzymatic electrochemical detection of rutin on Pt nanoparticles/graphene nanocomposite modified glassy carbon electrode

In this article, a nonenzymatic electrochemical sensor based on chemically reduced graphene oxide (RGO) and a Pt nanoparticles (PtNPs) modified glassy carbon electrode has been fabricated and used to determine rutin. The nanocomposites of PtNPs/RGO were characterized by transmission electron microscopy and X-ray diffraction, and the electrochemical behaviors of rutin on PtNPs/RGO were demonstrated by cyclic voltammetry and differential pulse voltammetry. The as-fabricated electrochemical sensor for rutin exhibited a wide linear range from 0.057 to 102.59 μM with a detection limit of 0.02 μM (S/N = 3). Additionally, the as-prepared electrode displayed a good reproducibility, stability and anti-interference ability for the detection of rutin. Finally, the electrode was successfully applied for the determination of rutin in pharmaceutical tablets.

Rapid synthesis of platinum-ruthenium bimetallic nanoparticles dispersed on carbon support as improved electrocatalysts for ethanol oxidation

Bimetallic nanocatalysts with small particle size benefit from markedly enhanced electrocatalytic activity and stability during small molecule oxidation. Herein, we report a facile method to synthesize binary Pt-Ru nanoparticles dispersed on a carbon support at an optimum temperature. Because of its monodispersed nanostructure, synergistic effects were observed between Pt and Ru and the PtRu/C electrocatalysts showed remarkably enhanced electrocatalytic activity towards ethanol oxidation. The peak current density of the Pt1Ru1/C electrocatalyst is 3731 mA mg-1, which is 9.3 times higher than that of commercial Pt/C (401 mA mg-1). Furthermore, the synthesized Pt1Ru1/C catalyst exhibited higher stability during ethanol oxidation in an alkaline medium and maintained a significantly higher current density after successive cyclic voltammograms (CVs) of 500 cycles than commercial Pt/C. Our work highlights the significance of the reaction temperature during electrocatalyst synthesis, leading to enhanced catalytic performance towards ethanol oxidation. The Pt1Ru1/C electrocatalyst has great potential for application in direct ethanol fuel cells.