Fabrication and Characterization of Inorganic Silver and Palladium Nanostructures within Hexagonal Cylindrical Channels of Mesoporous Carbon

Abstract

Abstract:In this study, we prepared a mesoporous carbon with hexagonally packed mesopores through evaporation-induced self-assembly (EISA)-with the diblock copolymer poly(ethylene oxide-b-ε-caprolactone) (PEO-b-PCL) as the template (EO 114 CL 84 ), phenolic resin as the carbon precursor, hexamethylenetetramine (HMTA) as the curing agent, and star octakis-PEO-functionalized polyhedral oligomeric silsesquioxane (PEO-POSS) as the structure modifier-and subsequent carbonization. We then took the cylindrical mesoporous carbon as a loading matrix, with AgNO 3 and Pd(NO 3 ) 2 as metal precursors, to fabricate Ag nanowire/mesoporous carbon and Pd nanoparticle/mesoporous carbon nanocomposites, respectively, through an incipient wetness impregnation method and subsequent reduction under H 2 . We used transmission electron microscopy, electron diffraction, small-angle X-ray scattering, N 2 isotherm sorption experiment, Raman spectroscopy, and power X-ray diffraction to investigate the textural properties of these nanometal/carbon nanocomposites. Most notably, the Raman spectra of the cylindrical mesoporous carbon, Ag/mesoporous carbon, and Pd/mesoporous carbon revealed interesting phenomena in terms of the ratios of the intensities of the D and G bands (I D /I G ), the absolute scattering intensities, and the positions of the D bands.

Structure and energetics of SiOC and SiOC‐modified carbon‐bonded carbon fiber composites

“…Raman spectroscopy was performed to analyze structural evolution of the free carbon phase (Figure ). The Raman spectrum exhibits two major bands attributed to the D band (~1355 cm −1 ) and G band (~1608 cm −1 ) of the free carbon phase, which are assigned to the disordered carbon (turbostratic carbon layers or nanographitic domains) and graphitized carbon (in‐plane displacement of carbon atoms in hexagonal carbon sheets), respectively . These bands can vary in intensity, position, and width depending on the structural ordering of carbon, and the relative parameters are listed in Table .…”

One-step preparation of microporous Pd@cPIM composite catalyst film for triphasic electrocatalysis

“…Figures 1A and 1B show TEM data for Pd@cPIM and for cPIM. The electron diffraction pattern ( Figure 1C) confirms the presence of Pd nanoparticles [18], which are typically 10 to 30 nm in diameter. SEM data suggest typical flake sizes of 1-20 m with a thickness of about 0.1 m ( Figure 1D).…”

Fabrication of Shape‐Controlled Palladium Nanoparticle‐Decorated Electrospun Polypyrrole/Polyacrylonitrile Nanofibers for Hydrogen Peroxide Coalescing Detection

“…The two characteristic D and G peaks observed for the PPy/PAN NFs corresponded to stretching of the π‐conjugated structure and the ring‐stretching mode of PPy, whereas the PAN NFs spectrum only displays the nearly featureless. The I D / I G ratio of the SPd_PPy/PAN NFs was higher than that of the PPy/PAN NFs, which implied that the decoration of Pd within the PPy decreased the degree of graphitization . The chemical composition was investigated using XPS.…”