11 research outputs found
Nitrogen-Doped Nanoporous Carbons for Selective Separation of Ar/Kr/Xe/Rn Gases: An Experiment-Based Simulation Study
It is still a challenge
to find high-efficiency adsorbents for
the separation of noble gases. In this work, we combine the grand
canonical Monte Carlo (GCMC) simulation and adsorption integral equation
to theoretically characterize the pore size distribution (PSD) of
experimentally synthesized nitrogen-doped nanoporous carbon (Carbon-ZX)
and further predict the selectivity of Carbon-ZX for Xe/Kr, Xe/Ar,
and Rn/N<sub>2</sub> mixtures. Results indicate that the selectivities
of Carbon-ZX for Xe/Kr and Xe/Ar apparently are greater than that
of other MOFs in the same conditions, which also is further confirmed
by Henry’s constant and isosteric adsorption heat. Moreover,
the Carbon-ZX for the Rn/N<sub>2</sub> binary mixture shows the extremely
high selectivity (about 800–1200) in the molar fraction <i>X</i><sub>Rn</sub> < 0.001, which means that Carbon-ZX is
a promising candidate for indoor Rn capture. In short, this work provides
a useful method to characterize the experimentally synthesized nanoporous
materials and further explores their applications in adsorption and
separation
Inhibitory Effect of Furanic and Phenolic Compounds on Exoelectrogenesis in a Microbial Electrolysis Cell Bioanode
The
objective of this study was to systematically investigate the
inhibitory effect of furfural (FF), 5-hydroxymethylfurfural (HMF),
syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid
(HBA), which are problematic lignocellulose-derived byproducts, on
exoelectrogenesis in the bioanode of a microbial electrolysis cell.
The five compound mixture at an initial total concentration range
from 0.8 to 8.0 g/L resulted in an up to 91% current decrease as a
result of exoelectrogenesis inhibition; fermentative, nonexoelectrogenic
biotransformation pathways of the five compounds were not affected.
Furthermore, the parent compounds at a high concentration, as opposed
to their biotransformation products, were responsible for the observed
inhibition. All five parent compounds contributed to the observed
inhibition of the mixture. The IC<sub>50</sub> (i.e., concentration
resulting in 50% current decrease) of individually tested parent compounds
was 2.7 g/L for FF, 3.0 g/L for HMF, 1.9 g/L for SA, 2.1 g/L for VA
and 2.0 g/L for HBA. However, the parent compounds, when tested below
their respective noninhibitory concentration, jointly resulted in
significant inhibition as a mixture. Catechol and phenol, which were
persistent biotransformation products, inhibited exoelectrogenesis
only at high concentrations, but to a lesser extent than the parent
compounds. Exoelectrogenesis recovery from inhibition by all compounds
was observed at different rates, with the exception of catechol, which
resulted in irreversible inhibition
Design of the Alkali-Metal-Doped WO<sub>3</sub> as a Near-Infrared Shielding Material for Smart Window
Development
of new WO<sub>3</sub>-based material is significantly
important for smart-window applications. In this work, the electronic
properties of alkali metals monodoped (A<sub>0.083</sub>WO<sub>3</sub>, A = Li, Na, K, Rb, and Cs) and codoped (Li<sub>0.083</sub>A<sub>0.083</sub>WO<sub>3</sub>, A = Li, Na, K, Rb, and Cs) hexagonal WO<sub>3</sub> (hex-WO<sub>3</sub>) were investigated by employing the hybrid
functional method. It is found that codoping is more stable than monodoping
except in the case of (Li, Li). In the monodoped and codoped systems,
the Fermi level moves into the conduction band and shows metal-like
characteristic, which is responsible for the optical absorption in
the visible light and NIR absorption range. In addition, the codoped
systems exhibit strong NIR absorption which is not found in the pure
hex-WO<sub>3</sub>. Our results show that (Li, Cs) codoped hex-WO<sub>3</sub> is the most stable among these systems, showing excellent
NIR-shielding property, which is promising for energy-saving smart-window
applications
Synthesis of Cyano-Containing Phenanthridine Derivatives via Catalyst‑, Base‑, and Oxidant-Free Direct Cyanoalkylarylation of Isocyanides
An
efficient catalyst-, base-, and oxidant-free direct cyanoalkylarylation
of isocyanides with AIBN has been developed under mild conditions.
This strategy provides an elusive and rapid access to a wide range
of cyano-containing phenanthridine derivatives in good yields via
a one-pot alkylation/cyclization radical-cascade process. The mild
reaction conditions together with no need of any catalyst, base, or
oxidant make this protocol environmentally benign and practical
N‑Heterocyclic Carbene/Lewis Acid Catalyzed Enantioselective Aerobic Annulation of α,β-Unsaturated Aldehydes with 1,3-Dicarbonyl Compounds
A novel
and efficient aerobic asymmetric cyclization reaction of
cinnamaldehydes and 1,3-dicarbonyl compounds through oxidative NHC-catalysis
has been developed, and it allows the synthesis of a wide range of
enantiomeric enriched dihydropyranone derivatives in good yields with
good to excellent enantioselectivities. Various α,β-unsaturated
aldehydes with aliphatic and aromatic substitution groups and 1,3-dicarbonyl
compounds were well tolerated. The air was directly used as the oxidant,
which made this asymmetric cyclization reaction in a highly efficient,
cheap, and green manner
Computer Screening of Dopants for the Development of New SnO<sub>2</sub>‑Based Transparent Conducting Oxides
Transparent
conducting oxides (TCOs) are unique materials with
high electrical conductivity and optical transparency and have been
extensively used in optoelectronic devices. However, the prototype
n-type TCO, Sn-doped In<sub>2</sub>O<sub>3</sub> (ITO), is limited
by the rarity and high cost of indium. In contrast, SnO<sub>2</sub> is a promising alternative candidate, which is a low-cost and nontoxic
material and also exhibits electrical and optical properties, compared
to those of ITO. Here, we present a first-principles-based computer
screening system to search for suitable dopants for monodoping or
codoping SnO<sub>2</sub> to develop new SnO<sub>2</sub>-based TCO
materials. The screening is based on an efficient and reliable way
of calculating the effective mass, the band gap, the formation energy,
and the binding energy. The outcomes of the screening include all
already known successful SnO<sub>2</sub>-based TCO materials (Sb-doped
SnO<sub>2</sub>, ATO; F-doped SnO<sub>2</sub>, FTO) and also some
new ones (P-doped SnO<sub>2</sub>, PTO; F and P codoped SnO<sub>2</sub>, FPTO), which would be hopeful materials of interest for further
experimental validation
Rapid Access to Spirocylic Oxindoles: Application of Asymmetric N‑Heterocyclic Carbene-Catalyzed [3 + 3] Cycloaddition of Imines to Oxindole-Derived Enals
A chiral
N-heterocyclic carbene (NHC)-catalyzed [3 + 3] cycloaddition
reaction of imines and oxindole-derived enals was developed for rapid
access to spirocylic oxindoles. In most cases, the desired spirocylic
oxindole products were obtained in high yields and excellent enantioselectivities
with less than 1 h of reaction time
Enantioselective Construction of Spirocyclic Oxindole Derivatives with Multiple Stereocenters via an Organocatalytic Michael/Aldol/Hemiacetalization Cascade Reaction
An efficient organocatalytic Michael/aldol/hemiacetalization
cascade
reaction for construction of enantioenriched spirocyclic oxindoles
fused with tetrahydropyrane has been developed. The desired highly
functionalized 5′,6′-dihydro-2′<i>H</i>,4′<i>H</i>-spiroÂ[indoline-3,3′-pyran]-2-one
derivatives containing multiple stereogenic centers were obtained
in moderate to high chemical yields and with high stereoselectivities
Fabricating Transparent Multilayers with UV and Near-IR Double-Blocking Properties through Layer-by-Layer Assembly
We have fabricated a transparent
composite film with UV and near-infrared
(near-IR) double-blocking properties using polyethyleneimine (PEI),
indium tin oxide (ITO), and zinc oxide (ZnO) through layer-by-layer
(LbL) assembly under an ultrasonic field. By applying ultrasonic-assisted
LbL assembly, the aggregation of nanoparticles has been excluded,
resulting in a flatter and more transparent (visible range) film than
that obtained under conventional LbL assembly. Moreover, the effects
of the ultrasonic field are discussed in terms of the fact that the
transformation between the states of PEI/ITO films assembled with
or without ultrasonic field was reversible. To enhance the UV-blocking
properties in the most damaging region (290–350 nm), we incorporated
ZnO nanoparticles, which can block UV rays below 350 nm, and the obtained
hybrid multilayer displayed a high transparency of over 85% (visible
range) and good UV-/near-IR double-blocking effects that shielded
nearly 80% of the UV rays under 350 nm and 80% of the IR radiation
above 1600 nm
Enantioselective Construction of Spirocyclic Oxindole Derivatives with Multiple Stereocenters via an Organocatalytic Michael/Aldol/Hemiacetalization Cascade Reaction
An efficient organocatalytic Michael/aldol/hemiacetalization
cascade
reaction for construction of enantioenriched spirocyclic oxindoles
fused with tetrahydropyrane has been developed. The desired highly
functionalized 5′,6′-dihydro-2′<i>H</i>,4′<i>H</i>-spiroÂ[indoline-3,3′-pyran]-2-one
derivatives containing multiple stereogenic centers were obtained
in moderate to high chemical yields and with high stereoselectivities