ABSTRACT
The
electronic
structure
and
hydrogen
storage
properties
of
benzene‐based
covalent
organic
frameworks
(COFs)
with
pore
diameters
0.53,
0.99,
1.45
nm
are
studied
using
density
functional
theory
calculations.
COFs
show
poor
H
2
molecule
adsorption
properties.
To
enhance
their
properties,
Y
atoms
decorated
on
the
an
average
binding
energy
about
5–6
eV
per
atom.
Each
atom
Y‐decorated
COFs,
YCOF1,
YCOF2,
YCOF3
effectively
adsorbs
six
molecules
−0.28,
−0.34,
−0.35
molecule,
respectively.
capacity
is
found
to
be
4.7%,
5.1%,
6.5%
desorption
temperatures
358,
434,
447
K,
findings
that
a
larger
diameter
provides
more
space
for
metal
decoration
thereby
increases
capacity.
weight
percentage
meets
target
suggested
by
U.S.
Department
Energy
Fuel
Cells
Hydrogen
Joint
Undertaking
(FCH‐JU)
in
Europe.
This
paper
examines
the
integration
of
hydrogen
storage
in
renewable-intensive
energy
systems.
Current
technology
is
too
costly
and
inefficient,
but
reducing
costs
to
12.5%
current
levels
increasing
round-trip
efficiency
70%
could
make
it
competitive.
These
are
challenging
targets
feasible
given
positive
predictions
on
cost
reduction
attainability
currently.
Hydrogen
reduces
total
system
by
partly
replacing
lithium
batteries
lower
costs,
due
its
suitability
for
long-term
storage,
while
grid
flexibility
transmission
costs.
Moreover,
integrating
can
decrease
share
nuclear
fossil
fuels
generation
mix,
Italy
Germany
identified
as
primary
expansion
Europe.
In
scenarios
limited
supply,
becomes
more
competitive
essential
compensate
capacity
shortages,
though
may
not
reduce
