Rationally
designing the core/shell architecture of Pt-based electrocatalysts
has been demonstrated as an effective way to induce a surface strain
effect for promoting the sluggish kinetics of the oxygen reduction
reaction (ORR) at the cathode of fuel cells. However, unstable core
dissolution and structural collapse usually occur in Pt-based core/shell
catalysts during the long-term cycling operation, greatly impacting
actual fuel cell applications. Impeding the dissolution of cores beneath
the Pt shells is the key to enhancing the catalytic stability of materials.
Herein, a method for sandwiching atomic PdAu interlayers into one-dimensional
(1D) Pd/Pt core/shell nanowires (NWs) is developed to greatly boost
the catalytic stability of subnanometer Pt shells for ORR. The Pd/PdAu/Pt
core/shell/shell NWs display only 7.80% degradation of ORR mass activity
over 80 000 potential cycles with no dissolution of Pd cores
and good preservation of the holistic sandwich core/shell nanostructures.
This is a significant improvement of electrocatalytic stability compared
with the Pd/Pt core/shell NWs, which deformed and inactivated over
80 000 potential cycles. The density functional theory (DFT)
calculations further demonstrate that the electron-transfer bridge
Pd and electron reservoir Au, serving in the PdAu atomic interlayer,
both guarantee the preservation of the high electroactivity of surface
Pt sites during the long-term ORR stability test. In addition, the
Pd/PdAu/Pt NWs show a 1.7-fold higher mass activity (MA) for ORR than
the conventional Pd/Pt NWs. The enhanced activity can be attributed
to the strong interaction between PdAu interlayers and subnanometer-Pt
shells, which suppresses the competitive Pd-4d bands and boosts the
surface Pt-5d bands toward the Fermi level for higher electroactivity,
proved from DFT.
A multihierarchical structure with (NH 4 )(Ni, Co)PO 4 • 0.67H 2 O microplatelets and (Ni, Co) 3 (PO 4 ) 2 •8H 2 O ultrathin nanopieces anchored on reduced graphene oxide (NCNP/RGO) is synthesized via a mild hydrothermal approach. This unique interface-rich structure is suitable for a high power energy storage device by providing efficient pathways for both electronic conduction and ionic transportation, which are effective ways to improve the electrochemical performance. Specifically, a specific capacity of 993 F g −1 is obtained in the three-electrode measurement, with ultrahigh capacity retention of 81.2% (807 F g −1 ) from 0.5 to 32 A g −1 . The hybrid device constructed with the as-prepared NCNP/RGO as anode and a hierarchical porous carbon (HPC) as cathode offers a very superior energy density of 42.1 Wh kg −1 at a power density of 73 W kg −1 , which remains 32 Wh kg −1 at 14 kW kg −1 . Meanwhile, the as-prepared hybrid capacitor exhibits a remarkable cycling stability (96.5% capacitance retention after 10 000 cycles). The capacity contribution of capacitive behavior for the hybrid device is analyzed as 91.1% at 25 mV s −1 .
A simple and sensitive high-performance liquid chromatography (HPLC) method is developed and validated for simultaneous determination of pantoprazole and its two metabolites (pantoprazole sulfone and pantoprazole thioether) in dog plasma and applied to a pharmacokinetic study in Beagle dogs. Following a protein precipitation procedure, the samples are separated using reversed-phase HPLC (C18) by a gradient of acetonitrile and ammonium acetate (pH 6.0) at a flow rate of 1.0 mL/min and quantitated using UV detection at 290 nm. Omeprazole is selected as the internal standard. The method has a lower limit of quantitation of 0.025 microg/mL for pantoprazole and its two metabolites, using 0.1-mL aliquots of plasma. The linear calibration curves are obtained in the concentration range of 0.025-10.0 microg/mL for three analytes. The intra- and interrun precision (relative standard deviation), calculated from quality control (QC) samples, is less than 13% for three analytes. The accuracy determined from QC samples is between -6.4% and 12%.
Artemiaegg shells have an asymptotic sized pore structure (pore diameter: 500 nm–2500 nm), which could be used as a porous carrier for the preparation of nanocomposite materials. The objective of the present study was to prepare shell-supported TiO2using a naturally porous carrier,Artemiaegg shell, and to exhibit a case study of shell-supported TiO2for formaldehyde removal. Characterization of shell-TiO2using SEM-EDS, TEM, and XRD proved thatArtemiashell with asymptotic reduction pores (pore diameter: 500 nm–2500 nm) can be used as the carrier for nanocomposite materials.Artemiaegg shell-supported TiO2in polycrystalline-like nanostructures can be used for the high efficiency removal (adsorption and degradation) of formaldehyde under visible light. Our results suggest that iron, one of the shell’s components, should broaden the absorption of visible light and enhance the photocatalytic efficiency of nanotitanium dioxide under visible light. Due to their interesting absorption and formaldehyde removal qualities,Artemiaegg shell, as a novel naturally porous carrier for nanocomposite materials preparation, especially in the preparation of nanocatalysts, is worthy of further study.
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