5 research outputs found
Synthesis of Triazine-Based Porous Organic Polymers Derived N‑Enriched Porous Carbons for CO<sub>2</sub> Capture
Porous
carbon with both high CO<sub>2</sub> uptake and CO<sub>2</sub>/N<sub>2</sub> selectivity is desired for reducing the cost of carbon
capture. Here, we report the preparation of N-enriched porous carbons
(NPCs) derived from the low-cost triazine-based porous organic polymers
using KOH as the activating agent under N<sub>2</sub>. The results
indicate that the nitrogen content and textural properties of the
NPCs can be effectively adjusted by the polymer precursors and the
carbonization temperature. Impressively, the NPCs have an enriched
N content (5.56–11.33 wt %) and abundant porosity (BET surface
area: 394–1873 m<sup>2</sup>/g, pore volume: 0.27–1.56
cm<sup>3</sup>/g), endowing them with high CO<sub>2</sub> uptake (120–207
mg/g at 273 K and 1.0 bar) and acceptable CO<sub>2</sub>/N<sub>2</sub> selectivity (Henry’s law: 14.3–16.8). In particular,
the ultra micropore volume (<i>d</i> ≤ 0.8 nm) is
proven a key factor for the CO<sub>2</sub> uptake, while both the
ultra micropore volume and N content contribute the CO<sub>2</sub>/N<sub>2</sub> selectivity. Our described work will provide a strategy
to initiate developments of rationally designed porous carbons for
various potential applications
Biomimetic Mineralization Guided One-Pot Preparation of Gold Clusters Anchored Two-Dimensional MnO<sub>2</sub> Nanosheets for Fluorometric/Magnetic Bimodal Sensing
A novel
fluorometric/magnetic bimodal sensor is reported based
on gold nanoclusters (Au NCs)-anchored two-dimensional (2D) MnO<sub>2</sub> nanosheets (Au NCs–MnO<sub>2</sub>) that are synthesized
through a one-pot biomimetic mineralization process. Bovine serum
albumin (BSA) was used as the template to guide the formation and
assembly of the Au NCs–MnO<sub>2</sub> under physiological
conditions and without use of any strong oxidizing agent and toxic
surfactants as well as organic solvent. The fluorescence of Au NCs
was first quenched by MnO<sub>2</sub> nanosheets, while upon H<sub>2</sub>O<sub>2</sub> introduction, the MnO<sub>2</sub> nanosheets
can be sensitively and selectively reduced to Mn<sup>2+</sup> with
enhanced magnetic resonance (MR) signal and rapid recovery of Au NCs
fluorescence simultaneously. This dual-modal strategy can overcome
the weakness of a single-fluorescence detection mode. A linear range
of 0.06–2 μM toward H<sub>2</sub>O<sub>2</sub> was obtained
for the fluorescence mode, whereas the MR mode also allowed detection
of H<sub>2</sub>O<sub>2</sub> at a concentration that ranged from
0.01 to 0.2 mM. Benefiting from the BSA molecule residual on the product
surface, the as-prepared Au NCs–MnO<sub>2</sub> displays low
cytotoxicity and good biocompatibility. Importantly, the successful
application of Au NCs–MnO<sub>2</sub> for analysis of H<sub>2</sub>O<sub>2</sub> in biological samples and cells indicates that
the integration of Au NCs fluorescence with Mn<sup>2+</sup> MR response
provides a promising bimodal sensing platform for H<sub>2</sub>O<sub>2</sub> in vivo monitoring
Gelatin-Based Hydrogels Blended with Gellan as an Injectable Wound Dressing
Injectable
scaffolds are of great interests for skin regeneration
because they can fill irregularly shaped defects through minimally
invasive surgical treatments. In this study, an injectable hydrogel
from biopolymers is developed and its application as wound dressings
is examined. Gelatin-based hydrogels were successfully prepared at
body temperature upon blending with low content of gellan, and the
synergetic effect on the gel formation was carefully characterized
through rheological methods. The electrostatic complexation between
gelatin and gellan was confirmed to contribute a continuous hydrogel
network. The obtained blend hydrogel demonstrates remarkable shear-thinning
and self-recovering properties. For antibacterial purpose, tannic
acid was incorporated into the blend hydrogel. In addition, tannic
acid-loaded blend hydrogel was verified to accelerate the wound healing
on the mice model, significantly than the control groups. Thus, this
paper presents a facile approach without chemical modification to
construct injectable gelatin-based hydrogels, which have great potential
as a wound dressing or tissue scaffold at body temperature
MOF-Templated Fabrication of Hollow Co<sub>4</sub>N@N-Doped Carbon Porous Nanocages with Superior Catalytic Activity
Metallic
Co<sub>4</sub>N catalysts have been considered as one of the most
promising non-noble materials for heterogeneous catalysis because
of their high electrical conductivity, great magnetic property, and
high intrinsic activity. However, the metastable properties seriously
limit their applications for heterogeneous water phase catalysis.
In this work, a novel Co-metal–organic framework (MOF)-derived
hollow porous nanocages (PNCs) composed of metallic Co<sub>4</sub>N and N-doped carbon (NC) were synthesized for the first time. This
hollow three-dimensional (3D) PNC catalyst was synthesized by taking
advantage of Co-MOF as a precursor for fabricating 3D hollow Co<sub>3</sub>O<sub>4</sub>@C PNCs, along with the NH<sub>3</sub> treatment
of Co-oxide frames to promote the in situ conversion of Co-MOF to
Co<sub>4</sub>N@NC PNCs, benefiting from the high intrinsic activity
and electron conductivity of the metallic Co<sub>4</sub>N phase and
the good permeability of the hollow porous nanostructure as well as
the efficient doping of N into the carbon layer. Besides, the covalent
bridge between the active Co<sub>4</sub>N surface and PNC shells also
provides facile pathways for electron and mass transport. The obtained
Co<sub>4</sub>N@NC PNCs exhibit excellent catalytic activity and stability
for 4-nitrophenol reduction in terms of low activation energy (<i>E</i><sub>a</sub> = 23.53 kJ mol<sup>–1</sup>), high
turnover frequency (52.01 × 10<sup>20</sup> molecule g<sup>–1</sup> min<sup>–1</sup>), and high apparent rate constant (<i>k</i><sub>app</sub> = 2.106 min<sup>–1</sup>). Furthermore,
its magnetic property and stable configuration account for the excellent
recyclability of the catalyst. It is hoped that our finding could
pave the way for the construction of other hollow transition metal-based
nitride@NC PNC catalysts for wide applications
Oxygen Vacancy-Reinforced Water-Assisted Proton Hopping for Enhanced Catalytic Hydrogenation
Water-assisted
proton hopping (WAPH) has been intensively
investigated
for promoting the performance of metal oxide-supported catalysts for
hydrogenation. However, the effects of the structure of the metal
oxide support on WAPH have received little attention. Herein, we construct
oxygen vacancy-bearing, MoO3–x-supported
Pd nanoparticle catalysts (Pd/MoO3–x-R), where the oxygen vacancies can promote WAPH,
thereby facilitating catalytic hydrogenation. The experimental results
and theoretical calculations show that the oxygen vacancies favor
the adsorption of water, which assists the proton hopping across the
surface of the metal oxide, enhancing the catalytic hydrogenation.
Our finding will provide a potential approach to the design of metal
oxide-supported catalysts for hydrogenation