2 research outputs found
Face-Centered-Cubic Large-Pore Periodic Mesoporous Organosilicas with Unsaturated and Aromatic Bridging Groups
Large-pore ethenylene-bridged (−CHCH−)
and
phenylene-bridged (−C<sub>6</sub>H<sub>4</sub>−) periodic
mesoporous organosilicas (PMOs) with face-centered-cubic structure
(<i>Fm</i>3<i>m</i> symmetry) of spherical mesopores
were synthesized at 7 °C at low acid concentration (0.1 M HCl)
using Pluronic F127 triblock copolymer surfactant in the presence
of aromatic swelling agents (1,3,5-trimethylbenzene, xylenes–isomer
mixture, and toluene). In particular, this work reports an unprecedented
block-copolymer-templated well-ordered ethenylene-bridged PMO with
cubic structure of spherical mesopores and an unprecedented block-copolymer-templated
face-centered cubic phenylene-bridged PMO, which also has an exceptionally
large unit-cell size and pore diameter. The unit-cell parameters of
30 and 25 nm and the mesopore diameters of 14 and 11 nm (nominal BJH-KJS
pore diameters of 12–13 and 9 nm) were obtained for ethenylene-bridged
and phenylene-bridged PMOs, respectively. Under the considered reaction
conditions, the unit-cell parameters and pore diameters were found
to be similar when the three different methyl-substituted benzene
swelling agents were employed, although the degree of structural ordering
appeared to improve for phenylene-bridged PMOs in the sequence of
decreased number of methyl groups on the benzene ring
Near-Infrared- and Visible-Light-Enhanced Metal-Free Catalytic Degradation of Organic Pollutants over Carbon-Dot-Based Carbocatalysts Synthesized from Biomass
Cost-efficient
nanoparticle carbocatalysts composed of fluorescent
carbon dots (CDs) embedded in carbon matrix were synthesized via one-step
acid-assisted hydrothermal treatment (200 °C) of glucose. These
as-synthesized CD-based carbocatalysts have excellent photoluminescence
(PL) properties over a broad range of wavelengths and the external
visible or NIR irradiation on the carbocatalysts could produce electrons
to form electron–hole (e<sup>–</sup>–h<sup>+</sup>) pairs on the surface of carbocatalysts. These restant electron–hole
pairs will react with the adsorbed oxidants/reducers on the surface
of the CD-based carbocatalysts to produce active radicals for reduction
of 4-nitrophenol and degradation of dye molecules. Moreover, the local
temperature increase over CD-based carbocatalyst under NIR irradiation
can enhance the electron transfer rate between the organic molecules
and CD-based carbocatalysts, thus obviously increase the catalytic
activity of the CD-based carbocatalyst for the reduction of 4-nitrophenol
and the degradation of dye molecules. Such a type of CD-based carbocatalysts
with excellent properties and highly efficient metal-free photocatalytic
activities is an ideal candidate as photocatalysts for the reduction
of organic pollutants under visible light and NIR radiation