poster mrs hydrogen production
DESCRIPTION
poster presented during MRS 2015. DESIGN OF TITANIA NANOTUBE ARRAYS FOR THE PHOTOELECTROCATALYTIC WATER SPLITTING REACTIONTRANSCRIPT
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DESIGN OF TITANIA NANOTUBE ARRAYS FOR THE
PHOTOELECTROCATALYTIC WATER SPLITTING REACTION
P. J. Arias-Monje1*, F. J. Q. Corts1, H. Zea1, C. C. Luhrs2
This work was performed under the auspices of the National University of Colombia and Colciencias, grants number 19163 of the program Convocatoria del Programa Nacional de Proyectos para el Fortalecimiento de la Investigacin, la Creacin y la Innovacin en Posgrados de la Universidad Nacional de Colombia
2013-2015 and 21551 of the program Jvenes Investigadores de Colciencias - 2013, respectively. Many thanks as well to E.S.K. Menon and J. Phillips.
Acknowledgements
GOAL
2%
4%
6%
8%
10%
0 50 100 150
Ph
oto
curr
ent
effi
cien
cy(%
)
Aspect ratio (length/diameter)
150 nm 240 nm 320 nm2%
6%
9%
13%
16%
0 9 18 27
Ph
oto
curr
ent
effi
cien
cy (
%)
Number of rings
Diameter: 240 nmLength: 9 m
100
150
200
250
300
350
400
3 6 9
Dia
met
er (
nm
)
Water content (%)
0
5
10
15
20
25
1 10 100 1000
Tub
e le
ngt
h (
m
)
Anodizing time (min) Log scale
3.8%
6.9%
10.0%
Tube diameter and length vary linearly withwater content and anodizing time, respectively.
1National University of Colombia, Bogot, Colombia2Naval Postgraduate School, Monterey, CA, United States
Institutions
Water: 6.9% 10%
1st
step
2nd
step
Surface changes
Only diameter changes
Two-step anodizing increases uniformity atthe top of the arrays, regardless of the
water content.
To describe the photoelectrocatalytic (PEC)
response for hydrogen generation of the TiO2nanomaterial by tuning its morphology: diameter,
length and roughness.
Influence of diameter and tube length has not been
completely understood due to the difficulty of varying
them as independent variables and the fact that top
morphology variations can obscure those effects.
Dependence of morphology on synthesis conditions
(above)
Effect of morphology on the PEC response (1.6 mW/cm2
UVA light, Ni wire cathode, -0.5V bias vs. Ag/AgCl
reference electrode) (below)
Various roughness were obtained varying the
number of rings on the outer walls of the nanotubes
by alternating voltage anodizing
BA
CKG
RO
UN
D
The nanotubes were produced at 100 V in ethylene glycol
and ammonium fluoride solution
Photocurrent efficiency increases withthe number of rings, due to an increase
in the effective surface area without
compromising aspect ratio.
No rings 9 rings
Photocurrent efficiency depends on the aspectratio of the arrays (optimal value around 20)
PEC response of tubes of 240 nm of diameter, 9 m of
length and different number of rings
CO
NC
LUSI
ON
S