5 research outputs found
Nitrogen-Doped Porous Carbons Derived from Carbonization of a Nitrogen-Containing Polymer: Efficient Adsorbents for Selective CO<sub>2</sub> Capture
Because
of their abundant porosity, tunable surface properties,
and high stability, N-doped porous carbons (NPCs) are highly promising
for CO<sub>2</sub> capture. Carbonization of N-containing polymers
is frequently used for the preparation of NPCs, while such an approach
is hindered by the high cost of some polymer precursors. In the present
study, we report for the first time the fabrication of NPCs through
the rational choice of the low-cost, N-rich polymer NUT-2 (NUT indicates
Nanjing Tech University) as the precursor, which was obtained from
polymerization of easily available monomers under mild conditions
in the absence of any catalysts. Through carbonization at different
temperatures (500–800 °C), NPCs with various porosity
and nitrogen contents are obtained. The pore structure and CO<sub>2</sub>-philic (N-doped) sites are responsible for the adsorption
performance, while the highest surface area does not lead to the highest
CO<sub>2</sub> adsorption capacity. For the sample carbonized at 600
°C (NPC-2-600), the adsorption capacity on CO<sub>2</sub> is
as high as 164.7 cm<sup>3</sup> g<sup>–1</sup> at 0
°C and 1 bar, which is much better than that of the benchmarks,
such as activated carbon (62.5 cm<sup>3</sup> g<sup>–1</sup>) and 13X zeolite (91.8 cm<sup>3</sup> g<sup>–1</sup>), as well as most reported carbon-based adsorbents. We also demonstrate
that the present NPCs can be regenerated completely under mild conditions.
The present adsorbents may provide promising candidates for the capture
of CO<sub>2</sub> from various mixtures, such as flue gas and natural
gas
Green Synthesis of Noble Nanometals (Au, Pt, Pd) Using Glycerol under Microwave Irradiation Conditions
A newer
application of glycerol in the field of nanomaterials synthesis has
been developed from both the economic and environmental points of
view. Glycerol can act as a reducing agent for the fabrication of
noble nanometals, such as Au, Pt, and Pd, under microwave irradiation.
Their shapes can be changed by adding different surfactants. In the
presence of CTAB, Au nanosheets were formed within 2 min where the
size of Au nanosheets can be controlled by the microwave irradiation
time and glycerol content
Facile Fabrication of Cuprous Oxide-based Adsorbents for Deep Desulfurization
Deep
desulfurization via π-complexation adsorption is an
effective approach for the selective capture of aromatic sulfur compounds.
Among various Ï€-complexation adsorbents, CuÂ(I)-containing materials
attract great attention due to their low cost and high efficiency.
In the present study, a one-pot thermal treatment strategy was developed
to fabricate Cu<sub>2</sub>O-based adsorbents for the first time.
As-synthesized mesoporous silica SBA-15 was directly used as the support
and the precursor CuÂ(NO<sub>3</sub>)<sub>2</sub> was introduced to
the confined space between silica walls and template. The subsequent
one-pot thermal treatment plays a triple role by decomposing CuÂ(NO<sub>3</sub>)<sub>2</sub> to CuO, removing the template P123, and reducing
CuO to Cu<sub>2</sub>O. In contrast to the traditional approach, our
strategy provides a more convenient method for the preparation of
Cu<sub>2</sub>O-based adsorbents. For a typical material CuAS-3 derived
from as-synthesized SBA-15, the yield of CuÂ(I) is 73.3%, which is
obviously higher than its counterpart CuCS-3 prepared from template-free
SBA-15 (53.3%). We also demonstrate that the resultant materials are
active in adsorptive desulfurization, and the amount of thiophene
captured can reach 0.35 mmol·g<sup>–1</sup> over CuAS-3,
which is obviously better than that over CuCS-3 (0.27 mmol·g<sup>–1</sup>). Furthermore, the activity in adsorptive desulfurization
can be well recovered with no apparent loss. The convenient preparation,
high activity, and good reusability make the present materials highly
promising for utilization as adsorbents in deep desulfurization
Oriented Built-in Electric Field Introduced by Surface Gradient Diffusion Doping for Enhanced Photocatalytic H<sub>2</sub> Evolution in CdS Nanorods
Element doping has
been extensively attempted to develop visible-light-driven
photocatalysts, which introduces impurity levels and enhances light
absorption. However, the dopants can also become recombination centers
for photogenerated electrons and holes. To address the recombination
challenge, we report a gradient phosphorus-doped CdS (CdS-P) homojunction
nanostructure, creating an oriented built-in electric-field for efficient
extraction of carriers from inside to surface of the photocatalyst.
The apparent quantum efficiency (AQY) based on the cocatalyst-free
photocatalyst is up to 8.2% at 420 nm while the H<sub>2</sub> evolution
rate boosts to 194.3 μmol·h<sup>–1</sup>·mg<sup>–1</sup>, which is 58.3 times higher than that of pristine
CdS. This concept of oriented built-in electric field introduced by
surface gradient diffusion doping should provide a new approach to
design other types of semiconductor photocatalysts for efficient solar-to-chemical
conversion
Oriented Built-in Electric Field Introduced by Surface Gradient Diffusion Doping for Enhanced Photocatalytic H<sub>2</sub> Evolution in CdS Nanorods
Element doping has
been extensively attempted to develop visible-light-driven
photocatalysts, which introduces impurity levels and enhances light
absorption. However, the dopants can also become recombination centers
for photogenerated electrons and holes. To address the recombination
challenge, we report a gradient phosphorus-doped CdS (CdS-P) homojunction
nanostructure, creating an oriented built-in electric-field for efficient
extraction of carriers from inside to surface of the photocatalyst.
The apparent quantum efficiency (AQY) based on the cocatalyst-free
photocatalyst is up to 8.2% at 420 nm while the H<sub>2</sub> evolution
rate boosts to 194.3 μmol·h<sup>–1</sup>·mg<sup>–1</sup>, which is 58.3 times higher than that of pristine
CdS. This concept of oriented built-in electric field introduced by
surface gradient diffusion doping should provide a new approach to
design other types of semiconductor photocatalysts for efficient solar-to-chemical
conversion