ACS Sustainable Chemistry & Engineering,
Journal Year:
2024,
Volume and Issue:
13(1), P. 276 - 288
Published: Dec. 19, 2024
Catalytic
hydrodeoxygenation
(HDO)
of
bio-oil
is
an
effective
and
challenging
route
to
the
efficient
utilization
biomass
with
rich
oxygen-containing
groups.
Herein,
highly
dispersed
Pd
nanoparticles
(NPs)
anchored
on
a
N-doped
hollow
carbon
sphere
(NHCS)
were
constructed
effectively
catalyze
chemoselective
HDO
bio-oil-derived
vanillin.
The
optimized
Pd/NHCS-900
catalyst
presented
high
99%
conversion
98%
selectivity
2-methoxy-4-methylphenol
(MMP)
within
45
min
under
very
mild
conditions
50
°C
1
atm
H2.
incorporated
N
species
in
NHCS
support
its
hierarchical
porous
structure
facilitate
dispersion
stabilization
NPs,
resulting
formation
NPs
excellent
stability.
Moreover,
presence
strong
electronic
metal–support
interaction
between
produced
surface
electron-rich
active
which
could
enhance
adsorption
activation
reactants,
thereby
exhibiting
intrinsic
catalytic
activity
large
turnover
frequency
(TOF)
1700.3
h–1.
Kinetic
study
density
functional
theory
(DFT)
calculations
demonstrated
reaction
pathway
corresponding
mechanism.
These
findings
pave
way
for
development
stable
metal
catalysts
sustainable
conversion.
Hydrodeoxygenation
is
the
key
technology
for
realizing
conversion
of
biomass
into
high
value-added
chemicals,
but
usually
encounters
low
efficiency
and
harsh
conditions
due
to
rich
electron
density
strong
C-O
bonds
O-containing
groups.
Herein,
an
efficient
catalyst
precisely
constructed
with
abundant
acidic
O
dopants
well-exposed
oxidized
Pd
centers
hydrodeoxygenation
vanillin.
Through
a
tannic
acid-assisted
strategy,
it
on
alumina
that
electron-deficient
species
doped
as
ether
types
in
carbon
along
ultra-small
PdO
nanoparticles.
The
collaboration
sites
from
boosts
vanillin
valuable
2-methoxy-4-methylphenol
99%
yield
turnover
frequency
value
752
h-1
under
mild
(80
oC,
0.5
MPa
H2),
significantly
surpassing
similar
catalysts
without
or
well
commercial
heterogeneous
homogeneous
catalysts.
Further
theoretical
calculation
studies
disclose
are
superior
metallic
hydrogenating
aldehyde
group,
important
promoting
subsequent
alcohol-based
deoxygenation
process.
Converting
abundant
lignin
resources
into
high-value
chemicals
has
always
been
a
pivotal
approach
in
biomass
refining.
Among
various
methods,
catalytic
oxidative
depolymerization
stands
out
as
one
of
the
most
promising
approaches
due
to
its
mild
reaction
conditions
and
remarkable
efficiency.
In
this
study,
we
present
series
transition
metal-substituted
POM@MOF
catalysts,
among
which
NiPMo@UIO-66
demonstrated
superior
performance
after
thorough
characterization.
Upon
deeper
investigation,
it
was
found
that
under
optimal
160°C,
1.0
MPa
O2,
3
h,
synergistic
regulation
Brønsted
Lewis
acids
exceptional
redox
properties
POMs,
coupled
with
enhanced
substrate-catalyst
contact
opportunities
provided
by
MOF
support,
synergistically
controlled
formation
ensured
high
selectivity
(>90%)
primary
products,
vanillin
methyl
vanillate
(the
yield
11.26
wt%).
Furthermore,
stable
reusability
catalyst
guaranteed
UIO-66,
negligible
decline
observed
over
five
consecutive
recycling
experiments.
This
study
aims
provide
insightful
inspiring
contributions
design
catalysts
within
valorization
system.
