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Chemisorption Analysis
Chemical Adsorption by Static and Dynamic Methods
Chemisorption,
also
known
as
chemical
adsorption,
concerns
the
formation
of
chemical
bonds
between
an
adsorbate
species
and
the
active
surface
of
a
sample
material.
Chemisorption
is
particularly
suited
to
the
characterisation
and
optimisation
of
catalysts
but
it
can
also
be
applied
to
virtually
any
metallic
containing
species
on
an
inert
support
material,
irrespective
of
its
application.
Chemisorption
analysis
provides
essential
information
on
active
metal
surface
area,
dispersion
and
crystallite
size.
Essentially,
this
can
be
used
to
determine
the
availability
of
the
active
species
which
directly
determines
efficiency,
efficacy
and
capacity.
Such
investigations
are
applicable
throughout
a
products
life-cycle,
from
the
fabrication
process
to
investigating
degradation
during
use
and
ultimately
the
success
of
a
regeneration
process.
Further,
complimentary,
characterisations
are
also
available
via
Temperature
Programmed
Analysis
and
the
measurement
of
iso-steric
Heat
of
Adsorption,
more
details
are
available
on
their
respective pages.
Key Applications
Characterisation of availability of active species
Product formulation and process control
QC control of fabrication processes
Performance determination: efficiency and capacity
Assessment of chemical activity
Determination of performance loss of time and use
Success of re-generation processes
Standard analyses using CO and H
2
probe molecules
Specialised probe molecules: N
2
O for Cu analysis
At
MCA
Services
we
offer
two
different
chemisorption
techniques
applying
a
range
of
adsorbate
options,
meaning
that
most
active
metallic
species
can
be
analysed
and
characterised.
We
use
state-of-the-art
Micromeritics
3
Flex
(TCD)
and
AutoChem
II
instruments
which
ensure
analyses of great flexibility and precision.
The
static
chemisorption
method
is
undertaken
at
a
constant
analysis
temperature
over
a
range
of
relative
adsorption
pressures.
Two
adsorption
isotherms
are
recorded:
the
first
comprising
chemically
(strong)
and
physically
(weak)
adsorption
whilst
the
second
only
comprises
the
weak
physisorbed
adsorbate.
The
molar
volume
of
the
chemically
adsorbed
probe
molecule
can
then
be
determined
and
applied
to
the
calculation
of
active metal dispersion, surface area and crystallite size.
Dynamic,
or
pulse
chemisorption
is
undertaken
at
atmospheric
pressure
using
a
flowing
gas
stream
of
an
inert
carrier.
Successive
injections
of
a
calibrated
volume
of
the
adsorbate
gas
are
then
periodically
made
to
the
carrier
gas
and
a
Thermal
Conductivity
Detector
is
used
to
measure
the
volume
of
the
injection
not
chemically
adsorbed
to
the
sample
material.
Analysis
is
complete
when
no
further
adsorbate
is
chemically
adsorbed
to
the
sample
material.
The
total
volume
of
chemically
adsorbed
probe
molecule
can
the
be
ascertained
and
the
same
calculations
of
active
metal dispersion, surface area and crystallite size can be made.
Analytical Options and Highlights
Static chemisorption analysis
Dynamic (pulse) chemisorption analysis
Wide choice of analysis temperatures
Choice of adsorbate: H
2
, CO & N
2
O
Wide choice and flexibility of pre-reduction conditions
Active species dispersion (%)
Active species surface area and total sample surface area
Active species crystallite size
Complimentary Temperature Programmed Analyses
Complimentary Heat of Adsorption analysis
At
MCA
Services
we
have
decades
of
experience
in
the
analysis
and
characterisation
of
materials
by
chemisorption
and
are
always
happy
to
discuss
specific
samples
and
applications.
The
flexibility
of
our
analytical
options
combined
with
our
expertise
ensures
that
the
most
appropriate
analytical
test,
or
combination
of
tests,
are
selected
for
your
particular
sample,
application
and
requirements.
We
also
provide
assistance
with
the
interpretation
of
results
and
more
information
about
these
analytical
options
and
the
background
operation
and
theory
can
be
found
on
our
YouTube channel.
Key Applications
Characterisation of availability of active species
Product formulation and process control
QC control of fabrication processes
Performance determination: efficiency and capacity
Assessment of chemical activity
Determination of performance loss of time and use
Success of re-generation processes
Standard analyses using CO and H
2
probe molecules
Specialised probe molecules: N
2
O for Cu analysis
Chemisorption Analysis
Chemical Adsorption by Static and Dynamic Methods
Chemisorption,
also
known
as
chemical
adsorption,
concerns
the
formation
of
chemical
bonds
between
an
adsorbate
species
and
the
active
surface
of
a
sample
material.
Chemisorption
is
particularly
suited
to
the
characterisation
and
optimisation
of
catalysts
but
it
can
also
be
applied
to
virtually
any
metallic
containing
species
on
an
inert
support
material,
irrespective
of
its
application.
Chemisorption
analysis
provides
essential
information
on
active
metal
surface
area,
dispersion
and
crystallite
size.
Essentially,
this
can
be
used
to
determine
the
availability
of
the
active
species
which
directly
determines
efficiency,
efficacy
and
capacity.
Such
investigations
are
applicable
throughout
a
products
life-cycle,
from
the
fabrication
process
to
investigating
degradation
during
use
and
ultimately
the
success
of
a
regeneration
process.
Further,
complimentary,
characterisations
are
also
available
via
Temperature
Programmed
Analysis
and
the
measurement
of
isosteric
Heat
of
Adsorption,
more details are available on their respective pages.
At
MCA
Services
we
offer
two
different
chemisorption
techniques
applying
a
range
of
adsorbate
options,
meaning
that
most
active
metallic
species
can
be
analysed
and
characterised.
We
use
state-
of-the-art
Micromeritics
3
Flex
(TCD)
and
AutoChem
II
instruments
which
ensure
analyses
of
great
flexibility
and
precision.
The
static
chemisorption
method
is
undertaken
at
a
constant
analysis
temperature
over
a
range
of
relative
adsorption
pressures.
Two
adsorption
isotherms
are
recorded:
the
first
comprising
chemically
(strong)
and
physically
(weak)
adsorption
whilst
the
second
only
comprises
the
weak
physiosorbed
adsorbate.
The
molar
volume
of
the
chemically
adsorbed
probe
molecule
can
then
be
determined
and
applied
to
the
calculation
of
active metal dispersion, surface area and crystallite size.
Dynamic,
or
pulse
chemisorption
is
undertaken
at
atmospheric
pressure
using
a
flowing
gas
stream
of
an
inert
carrier.
Successive
injections
of
a
calibrated
volume
of
the
adsorbate
gas
are
then
periodically
made
to
the
carrier
gas
and
a
Thermal
Conductivity
Detector
is
used
to
measure
the
volume
of
the
injection
not
chemically
adsorbed
to
the
sample
material.
Analysis
is
complete
when
no
further
adsorbate
is
chemically
adsorbed
to
the
sample
material.
The
total
volume
of
chemically
adsorbed
probe
molecule
can
the
be
ascertained
and
the
same
calculations
of
active
metal
dispersion, surface area and crystallite size can be made.
Analytical Options and Highlights
Static chemisorption analysis
Dynamic (pulse) chemisorption analysis
Wide choice of analysis temperatures
Choice of adsorbate: H
2
, CO & N
2
O
Wide choice and flexibility of pre-reduction conditions
Active species dispersion (%)
Active species surface area and total sample surface area
Active species crystallite size
Characterisations by Temperature Programmed Analysis
Compli
mentary Heat of Adsorption analysis
At
MCA
Services
we
have
decades
of
experience
in
the
analysis
and
characterisation
of
materials
by
chemisorption
and
are
always
happy
to
discuss
specific
samples
and
applications.
The
flexibility
of
our
analytical
options
combined
with
our
expertise
ensures
that
the
most
appropriate
analytical
test,
or
combination
of
tests,
are
selected
for
your
particular
sample,
application
and
requirements.
We
also
provide
assistance
with
the
interpretation
of
results
and
more
information
about
these
analytical
options
and
the
background
operation
and
theory
can
be
found
on
our
YouTube channel.
