Abstract
Metal–organic
frameworks
and
covalent
organic
have
been
widely
employed
in
electrochemical
catalysis
owing
to
their
designable
skeletons,
controllable
porosities,
well‐defined
catalytic
centers.
However,
the
poor
chemical
stability
low
electron
conductivity
limited
activity,
single‐functional
sites
these
hindered
them
show
multifunctional
roles
systems.
Herein,
we
constructed
novel
metal
polymers
(Co‐HAT‐CN
Ni‐HAT‐CN)
with
dual
centers
(metal–N
4
metal–N
2
)
catalyze
oxygen
reduction
reaction
(ORR)
evolution
(OER).
By
using
different
centers,
activity
selectivity
were
well‐tuned.
Among
them,
Co‐HAT‐CN
catalyzed
ORR
a
4e
−
pathway,
half‐wave
potential
of
0.8
V
versus
RHE,
while
Ni‐HAT‐CN
2e
pathway
H
O
over
90%.
Moreover,
delivered
an
overpotential
350
mV
at
10
mA
cm
−2
corresponding
Tafel
slope
24
dec
−1
for
OER
1.0
M
KOH
aqueous
solution.
The
experimental
results
revealed
that
activities
toward
due
M–N
frameworks,
both
contributed
OER.
This
work
gives
us
new
platform
construct
bifunctional
catalysts.
Abstract
The
s
eparator
is
an
important
component
in
batteries,
with
the
primary
function
of
separating
positive
and
negative
electrodes
allowing
free
passage
ions.
Porous
organic
framework
materials
have
a
stable
connection
structure,
large
specific
surface
area,
ordered
pores,
which
are
natural
places
to
store
electrolytes.
And
these
functions
can
be
designed
according
needs
researchers.
performance
porous
framework‐based
separators
used
rechargeable
lithium
metal
batteries
much
better
than
that
polyethylene/propylene
separators.
In
this
paper,
three
most
classic
(MOF,
COF,
HOF)
analyzed
summarized.
applications
MOF,
HOF
lithium‐sulfur
anode,
solid
electrolytes
reviewed.
Meanwhile,
research
progress
different
fields
discussed
based
on
time.
Finally,
conclusion,
problems
encountered
by
as
well
their
future
priorities
presented.
This
review
will
provide
theoretical
guidance
for
design
further
stimulate
researchers
conduct
materials.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(51), С. 27984 - 27992
Опубликована: Дек. 15, 2023
Anion
exchange
membranes
with
high
anion
conductivity
are
highly
desired
for
electrochemical
applications.
Increasing
ion
capacity
is
a
straightforward
approach
to
enhancing
but
faces
challenge
in
dimensional
stability.
Herein,
we
report
the
design
and
preparation
of
three
kinds
isoreticular
covalent
organic
framework
(COF)
bearing
tunable
quaternary
ammonium
group
densities
as
conductors.
Therein,
cationic
groups
integrated
into
backbones
by
flexible
ether-bonded
alkyl
side
chains.
The
ammonium-group-functionalized
building
units
endow
COF
abundant
homogeneously
distributed
ordered
channels.
chains
alleviate
electrostatic
repulsion
steric
hindrance
caused
large
groups,
ensuring
tight
interlayer
stacking
multiple
interactions.
As
result,
our
achieve
exceptional
stability
simultaneously.
Furthermore,
effect
ionic
density
on
rigid
channels
systematically
explored.
Experiments
simulations
reveal
that
concentration
chain
mobility
jointly
determine
transport
behavior,
resulting
abnormal
phenomenon
not
positively
correlated
density.
optimal
membrane
achieves
ever-reported
highest
hydroxide
over
300
mS
cm-1
at
80
°C
100%
RH.
This
study
offers
insightful
guidelines
rational
high-performance
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(38)
Опубликована: Июль 27, 2023
Flexible
covalent
organic
frameworks
(COFs)
are
intriguing
for
their
dynamic
properties
distinctive
from
rigid
counterparts
but
still
suffer
limited
accessibility.
Especially,
controlling
flexibility
of
COFs
is
challenging
and
the
impact
different
on
has
rarely
been
unveiled.
This
article
reports
stepwise
adjustment
two-dimensional
COFs,
which
realized
by
designed
synthesis
COF
(R-COF),
semi-flexible
(SF-COF),
flexible
(F-COF)
through
polymerization,
linker
exchange,
linkage
conversion
with
a
newly
developed
method
reduction
hydrazone,
respectively.
Significant
difference
in
breathing
behavior
self-adaptive
capability
three
uncovered
vapor
response
iodine
capture
experiments.
Gas
sorption
experiments
indicate
that
porosity
F-COF
could
switch
"close"
state
nitrogen
to
"open"
carbon
dioxide,
not
observed
R-COF
SF-COF.
study
only
develops
strategy
adjust
tuning
linkers
linkages,
also
provides
deep
insight
into
lays
foundation
development
this
new
class
porous
materials.
Abstract
Metal–organic
frameworks
and
covalent
organic
have
been
widely
employed
in
electrochemical
catalysis
owing
to
their
designable
skeletons,
controllable
porosities,
well‐defined
catalytic
centers.
However,
the
poor
chemical
stability
low
electron
conductivity
limited
activity,
single‐functional
sites
these
hindered
them
show
multifunctional
roles
systems.
Herein,
we
constructed
novel
metal
polymers
(Co‐HAT‐CN
Ni‐HAT‐CN)
with
dual
centers
(metal–N
4
metal–N
2
)
catalyze
oxygen
reduction
reaction
(ORR)
evolution
(OER).
By
using
different
centers,
activity
selectivity
were
well‐tuned.
Among
them,
Co‐HAT‐CN
catalyzed
ORR
a
4e
−
pathway,
half‐wave
potential
of
0.8
V
versus
RHE,
while
Ni‐HAT‐CN
2e
pathway
H
O
over
90%.
Moreover,
delivered
an
overpotential
350
mV
at
10
mA
cm
−2
corresponding
Tafel
slope
24
dec
−1
for
OER
1.0
M
KOH
aqueous
solution.
The
experimental
results
revealed
that
activities
toward
due
M–N
frameworks,
both
contributed
OER.
This
work
gives
us
new
platform
construct
bifunctional
catalysts.
