Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
61(13)
Опубликована: Янв. 24, 2022
The
ordered
open
organic
frameworks
membranes
are
attractive
candidates
for
flow-assisted
molecular
separations.
physicochemical
properties
of
such
mostly
depend
on
their
selectively
chosen
functional
building
blocks.
In
this
work,
we
have
introduced
a
novel
concept
switchability
three-dimensional
covalent
framework
(3D-COF)
through
simple
solvent-influenced
fragmentation
method.
This
room-temperature
interfacial
synthesis
provides
free-standing
3D-COF
with
distinct
from
the
same
monomers.
Notably,
change
solvent
chloroform
to
ethyl
acetate
switches
membrane
property
hydrophilic
(water
contact
angle
60°)
hydrophobic
142°)
nature.
passes
oil
molecules
an
oil-water
emulsion
gravitational
flux
1536
L
m-2
h-1
.
Dual‐metal
atom
catalysts
have
been
demonstrated
to
display
higher
catalytic
activity
and
selectivity
than
that
of
solo
metal
toward
oxygen
reduction
reaction
(ORR).
However,
it
is
difficult
construct
synergistic
sites
between
different
atoms
even
though
they
are
immobilized
in
the
same
support,
because
their
low‐density
distribution
resulted
long
distance
each
other.
Herein,
a
bimetal
atomic
electrocatalyst
for
ORR,
which
has
highly
dense
Zn‐N
4
(12.2
wt.%
Zn)
Fe‐N
O
sites,
from
core–shell
hybrid
covalent
organic
framework
(COF)
metal–organic
(MOF)
demonstrated.
The
resultant
catalyst
displays
high
ORR
with
half‐wave
potential
0.89
V
vs
reversible
hydrogen
electrode
(RHE)
0.1
m
KOH,
50
mV
more
positive
Pt/C.
operando
ANES
confirms
both
Zn
Fe
as
active
centers,
demonstrates
process.
Density
functional
theory
(DFT)
calculations
further
confirm
effect
enables
improve
ORR.
This
work
provides
new
insight
develop
COFs
MOFs.
Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
62(4)
Опубликована: Ноя. 26, 2022
The
application
of
three-dimensional
(3D)
covalent
organic
frameworks
(COFs)
in
renewable
energy
fields
is
greatly
limited
due
to
their
non-conjugated
skeletons.
Here,
we
design
and
successfully
synthesize
a
thiophene-enriched
fully
conjugated
3D
COF
(BUCT-COF-11)
through
an
all-thiophene-linked
saddle-shaped
building
block
(COThTh-CHO).
BUCT-COF-11
exhibits
excellent
semiconducting
property
with
intrinsic
metal-free
oxygen
reduction
reaction
(ORR)
activity.
Using
the
as
cathode
catalyst,
assembled
anion-exchange
membrane
fuel
cells
(AEMFCs)
exhibited
high
peak
power
density
up
493
mW
cm-2
.
DFT
calculations
reveal
that
thiophene
introduction
not
only
improves
conductivity
but
also
optimizes
electronic
structure
sample,
which
therefore
boosts
ORR
performance.
This
first
report
on
COFs
catalysts
cells,
demonstrating
great
potential
promising
semiconductors
fields.
Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
61(41)
Опубликована: Авг. 16, 2022
Covalent
organic
frameworks
(COFs)
having
high
specific
surface
area,
tunable
pore
size
and
crystallinity
are
mostly
post
modified
following
fluorine-based
complex
synthetic
approaches
to
achieve
a
bio-inspired
liquid
wettability,
i.e.
superhydrophobicity.
Herein,
facile,
non-fluorinated
robust
chemical
approach
is
introduced
for
tailoring
the
water
wettability
of
new
COF-which
was
prepared
through
Schiff-base
condensation
reaction.
A
silane
precursor
readily
reacted
with
selected
alkyl
acrylates
1,4-conjugate
addition
reaction,
prior
grafting
on
C4-COF
different
wettability-including
The
superhydrophobic
(SH-C4-COF)
that
displayed
significantly
enhanced
(>5
times;
from
220
wt.
%
1156
%)
oil-absorption
capacity,
extended
address
relevant
challenges
"oil-in-water"
emulsion
separation,
rapidly
(<1
minute)
repetitively
(50
times)
at
diverse
harsh
conditions.
Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
61(13)
Опубликована: Янв. 24, 2022
The
ordered
open
organic
frameworks
membranes
are
attractive
candidates
for
flow-assisted
molecular
separations.
physicochemical
properties
of
such
mostly
depend
on
their
selectively
chosen
functional
building
blocks.
In
this
work,
we
have
introduced
a
novel
concept
switchability
three-dimensional
covalent
framework
(3D-COF)
through
simple
solvent-influenced
fragmentation
method.
This
room-temperature
interfacial
synthesis
provides
free-standing
3D-COF
with
distinct
from
the
same
monomers.
Notably,
change
solvent
chloroform
to
ethyl
acetate
switches
membrane
property
hydrophilic
(water
contact
angle
60°)
hydrophobic
142°)
nature.
passes
oil
molecules
an
oil-water
emulsion
gravitational
flux
1536
L
m-2
h-1
.
