Visible light assisted hydrogen generation from complete decomposition of hyd...
7362
1. Introduction
q We
face
an
increasing
need
for
renewable
energy
sources
and
clean
environment
q Photocatalysis
is
a
promising
approach
to
harvest
solar
energy
and
decompose
organic
pollutants
q Titanium
Dioxide
(TiO2)
is
the
most
extensively
studied
photo-‐
catalyst,
but
it
requires
ultraviolet
light
to
funcCon
Experimental Methods
Hydrothermal Synthesis Microscopic Imaging
Experimental Results
Conclusions
q Higher
acid
concentraCons
inhibited
formaCon
of
rods;
q Higher
calcinaCon
temperatures
led
to
thinner
rods;
q Longer
hydrothermal
treatment
Cmes
promoted
formaCon
of
rods;
q TiO2
prepared
using
nitric
acid
showed
the
best
acCvity
in
visible
light
dye
degradaCon,
while
maintaining
a
robust
morphology
at
different
acid
concentraCons;
q The
use
of
phosphoric
and
hydrochloric
acid
resulted
in
unique
morphology
but
the
resulCng
TiO2
materials
were
not
efficient
in
visible
light
photocatalysis.
Acknowledgements
Dr. Gonghu Li’s Group
Dr. Mark Townley
Dr. Nancy Cherim
Dr. James Krzanowski
The Effect of Morphology on Titanium Dioxide Photocatalysis
Ram Subedi, Cameron McInnes, Gonghu Li*
XRD Analysis Photocatalysis Testing
The Trio McNair Scholars Program
ACS Norris/Richards Scholarship
NSF Career Award (#1352437)
University of New Hampshire
q Hydrothermal
treatment
of
Ctanium
nitride
(TiN)
with
acids
was
performed
using
different
acids,
acid
concentraCons,
calcinaCon
temperatures,
and
reacCon
Cmes.
q Products
were
then
characterized
using
various
techniques
Figure
1.
SEM
images
of
TiO2
synthesized
with
different
acids
(concentraCon
2
M)
Figure
2.
SEM
images
of
TiO2
synthesized
using
HCl
at
different
concentraCons
Figure
3.
SEM
images
of
TiO2
aSer
calcinaCon
at
different
temperatures
Figure
4.
SEM
images
of
TiO2
synthesized
with
varying
reacCon
Cmes
Figure
5.
(A)
Image
showing
different
powders
(a.
TiN;
b.
HCl-‐2M;
c.
PA-‐2M;
d.
NA-‐1M;
e.
NA-‐2M;
f.
NA-‐4M;
g.
P25-‐TiO2).
(B)
UV-‐visible
spectra
of
selected
samples
Figure
7.
Visible
light
photocatalyCc
degradaCon
of
a
dye
molecule
(methylene
blue)
using
different
TiO2
materials
Figure
6.
X-‐ray
diffracCon
pa^erns
of
different
TiO2
A B
e-‐
h+
hv O2
O2
-‐
H2O
•OH
Reactive
Oxygen
Species
Air
Purification
Water
Treatment
……
+
VOCs
CO2
H2O
HCl …
Semiconductor
(TiO2,
ZnO,
CdS)
e-‐ (conduction
band
electron);
h+ (valence
band
hole)
q We
invesCgate
the
effect
of
morphology
on
photocatalysis
and
the
use
of
dopant
to
improve
photoresponse
in
the
visible
light
region.
20 25 30 35 40 45 50 55 60
Intensity
(counts)
angle
(2θ)
Anatase
(25) Rutile
(27) TiN
(37) TiN
(43) Rutile
(55)Rutile
(36) Anatase
(48)
P25
HCl-‐2M-‐12hr-‐650°C
NA-‐2M-‐12hr-‐500°C
NA-‐2M-‐12hr-‐650°C
NA-‐3M-‐12hr-‐500°C
PA-‐2M-‐12hr-‐650°C
PA-‐2M-‐168hr-‐650°C
0
0.2
0.4
0.6
0.8
1
0 30 60 90 120
normalized
absorbance
time
(minutes)
NA-‐1M
NA-‐4M
NA-‐2M
NA-‐3M
P25
0
0.2
0.4
0.6
0.8
1
0 30 60 90 120
normalized
absorbance
time
(minutes)
NA-‐2M
P25
HCl-‐2M
PA-‐2M
