Search

In this study, a well-dispersed Pd nanoparticle (NP)-supported RGO/Mn3O4 (G/M/Pd) composite was synthesized by a clean synthetic route, where galvanic replacement reaction simply occurred between Mn3O4 and a palladium salt, thereby avoiding the use of harsh reducing and capping agents. The G/M/Pd composite served as a robust catalyst for the catalytic oxidation of hydroquinone (HQ) to benzoquinone (BQ) with H2O2 in an aqueous solution. Oxidation was completed in only 4 min, with a turnover frequency (TOF) of 3613 h−1; this TOF is one hundred times those of previously reported Pd- and Ag-based catalysts. The superior performance was related to the electronic inductive effect between Mn3O4 and Pd NPs, which was verified by density functional theory calculations. Trapping experiments revealed that the oxidation of HQ was considerably related to the ·OH radicals generated from the decomposition of H2O2. In addition, the influencing factors were further investigated, including catalyst and HQ concentrations, solution pH, solvents, and various inorganic and organic interferences. Moreover, the G/M/Pd catalyst exhibits diverse applications for the catalytic oxidation of HQ derivatives with high TOFs.

In this study, a well-dispersed Pd nanoparticle (NP)-supported RGO/Mn

Based on the excellent properties of dopamine (reduction, self-polymerization and adhesion), we designed a one-step and environment-friendly reduction route to synthesize and simultaneously functionalize polydopamine (PDA)–Ag–reduced graphene oxide (RGO) hybrid. The obtained PDA–Ag–RGO hybrid was characterized by transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, FT-IR and UV–vis analysis. Silver nanoparticles were uniformly dispersed on the surface of RGO sheets and coated with a thin PDA film. The hybrid exhibited good dispersivity in polar solvents (water and acetonitrile). Compared with Ag–RGO hybrid prepared via NaBH4 reduction and commercial Pd/C catalyst, PDA–Ag–RGO hybrid had better catalytic activity for the oxidation of hydroquinone to benzoquinone in the presence of H2O2. Moreover, the hybrid still retained superior catalytic activity over multiple cycles.

An electrochemical sensor based on Au nanoparticles (AuNPs)–poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene (AuNPs–PDDA-G) nanocomposite was fabricated for the sensitive detection of alkannin. The nanocomposite was characterized by X-ray diffraction, ultraviolet/visible spectra, scanning electron microscopy, and transmission electron microscopy. Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behaviors of alkannin on the AuNPs–PDDA-G nanocomposite film-modified glassy carbon electrode. This electrochemical sensor displayed satisfactory analytical performance for alkannin detection over a range from 5.0 nmol L−1 to 3.0 μmol L−1 with a detection limit of 1.4 nmol L−1 (S/N = 3). Moreover, the sensor also exhibited good reproducibility and stability, and could be used for the detection of alkannin in real samples with satisfactory results.

Monodisperse CoPt3 nanocrystals (NCs) have been synthesized in oleylamine solution by an organic solvothermal method. The NCs were ellipsoidal particles with a diameter around 6.6 nm and length around 10 nm with a good single crystal structure. Using CoPt3 NCs as catalysts, large-area boron nanowires with diameters ranging from 30 to 50 nm were successfully prepared by chemical vapor deposition using a C/B/B2O3 mixture as the precursor. Structural analysis indicated that these nanowires were single crystalline with a β-rhombohedral structure. Measurement of the field emission properties of boron nanowire films showed that the boron nanowires have good field emission characteristics. Open image in new window

Pt nanoparticles attached to the carbon nanotubes (CNTs)-modified polyimide (PIs) materials were successfully synthesized. Field emission scanning electron microscope (FE-SEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize this nanocomposite film, which has excellent stability and flexibility. The electrochemical study found that the Pt/PI/CNTs nanocomposite film exhibited remarkable electrocatalytic activity towards the oxidation of methanol and nitrite.

Studies of the electrochemical optimization of ZnSe thin film deposition on polycrystalline Au substrates using electrochemical atomic layer epitaxy are reported. Electrochemical aspects were characterized by means of cyclic voltammetry, differential pulse voltammetry, and coulometry. To study the growth mechanism of the underpotential deposition in the formation of ZnSe, the effects of Zn and Se deposition potentials and a Se-stripping potential were adjusted to optimize the deposition program. The deposit, grown using the optimized program, was proved to be a single-phase ZnSe compound with a strong (220)-preferred orientation by X-ray diffraction analysis, and scanning electronic microscopy observation shows the deposit consisted of nanoscale particles with an average size about 100 nm. The right 1:1 stoichiometric ratio of Zn to Se according to the coulometry suggests that ZnSe is formed.

To synthesize monodisperse palladium nanoparticles dispersed on reduced graphene oxide (RGO) sheets, we have developed an easy and scalable solvothermal reduction method from an organic solution system. The RGO-supported palladium nanoparticles with a diameter of 3.8 nm are synthesized in N-methyl-2-pyrrolidone (NMP) and in the presence of oleylamine and trioctylphosphine, which facilitates simultaneous reduction of graphene oxide and formation of Pd nanocrystals. So-produced Pd/RGO was tested for potential use as electrocatalyst for the electro-oxidation of formic acid. Pd/RGO catalyzes formic acid oxidation very well compared to Pd/Vulcan XC-72 catalyst. This synthesis method is a new way to prepare excellent electrocatalysts, which is of great significance in energy-related catalysis.