Copper nanoparticles-decorated polyaniline-derived mesoporous carbon that can serve as noble metal-free electrocatalyst for the hydrazine oxidation reaction (HzOR) is synthesized via a facile synthetic route. The material exhibits excellent electrocatalytic activity toward HzOR with low overpotential and high current density. The material also remains stable during the electrocatalytic reaction for long time. Its good electrocatalytic performance makes this material a promising alternative to conventional noble metal-based catalysts (e.g., Pt) that are commonly used in HzOR-based fuel cells.
We report a new hydroxyl functionalized microporous organic polymer (MOPOH) based on the polymerization of catechol with terephthalaldehyde using phenolic resin-inspired chemistry. This catechol-decorated material, with surface area of 874 m2 g−1 and micro, mesopores, facilitates the immobilization and dispersion of Pd nanoparticles (NPs) on the polymer matrix. The surface area of the created composite (Pd@MOPOH) decreases to 419 m2 g−1 and the pore size distribution is narrowly distributed at 1.54 nm due to the filling of mesopores. The CO2 capture capacities for MOPOH and Pd@MOPOH at 273 K and 1 bar are 13.4 and 9.2 wt%, respectively. The resultant Pd NPs are crystalline and uniform with a mean diameter of 4.8 nm. The well-dispersed Pd@MOPOH exhibits excellent catalytic activity toward the model reduction of 4-nitrophenol into 4-aminophenol. Significantly, nearly no Pd leaching is detected during the catalytic cycles, showing active and durable nature of the heterogeneous nanocatalyst. 相似文献
Pd nanoparticle catalysts supported by multiwall carbon nanotubes (Pd/MWNTs) prepared using a complexation–reduction method are used in this study for the electrochemical determination of hydrazine. The physico-chemical properties of the Pd/MWNT catalyst were characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and scanning electron microscopy physico-chemical (SEM). These structural analyses reveal that the Pd/MWNTs-modified glassy carbon electrode possesses a three-dimensional network structure in which the Pd nanoparticles, with an average size of 5 nm, are uniformly distributed on the surface of the MWNTs. After Nafion solution was coated on the surface of the Pd/MWNT layer, the resulting Pd/MWNT–Nafion modified electrode retained the three-dimensional network structure. Electrochemical measurements show that the oxidation peak current of hydrazine decreases with increasing pH. Under optimum conditions, the Pd/MWNT–Nafion-based hydrazine sensor exhibits a broad linear calibration range (2.5–700 μM) and a low detection limit of 1.0 μM for hydrazine. 相似文献
Silver nanoparticles (AgNPs) have been synthesized in the presence of polyacrylate through the reduction of silver nitrate by sodium borohydride in aqueous solution. The AgNO3 and polyacrylate carboxylate group concentrations were kept constant at 2.0 × 10–4 and 1.0 × 10–2 mol·L–1, respectively, while the ratio of [NaBH4]/[AgNO3] was varied from 1 to 100. The ultraviolet-visible plasmon resonance spectra of these solutions were found to vary with time prior to stabilizing after 27 d, consistent with changes of AgNP size and distribution within the polyacrylate ensemble occurring. These observations, together with transmission electron microscopic results, show this rearrangement to be greatest among the samples at the lower ratios of [NaBH4]/[AgNO3] used in the preparation, whereas those at the higher ratios showed a more even distribution of smaller AgNP. All ten of the AgNP samples, upon a one thousand-fold dilution, catalyze the reduction of 4-nitrophenol to 4-aminophenol in the temperature range 283.2–303.2 K with a substantial induction time being observed at the lower temperatures.
Au@TiO2 core/shell nanoparticles were synthesized by a simple and efficient one-step method using tetrabutyl titanate as TiO2 precursor. The samples were characterized by TEM, XRD, UV–vis and XPS. The experiments demonstrated that the average particles size of Au was 10–15 nm, and the thickness of TiO2 shell was 1–3 nm. TiO2 shell induced a red-shift of the absorption peak of Au. This material exhibited catalytic activity for CO oxidation. This study offered an approach for CO oxidation by using Au@TiO2 model catalysts. 相似文献