Hindawi Publishing Corporation
International Journal of Photoenergy
Volume 2010, Article ID 294217, 9 pages
doi:10.1155/2010/294217
Research Article
Characteristics of Carbon Monoxide Oxidization in Rich
Hydrogen by Mesoporous Silica with TiO
2
Photocatalyst
Akira Nishimura,
1
Yutaka Yamano,
1
Tomokazu Hisada,
1
Masafumi Hirota,
1
and Eric Hu
2
1
Division of Mechanical Engineering, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu 514-8507, Japan
2
School of Mechanical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia
Correspondence should be addressed to Akira Nishimura, nisimura@mach.mie-u.ac.jp
Received 17 August 2010; Accepted 9 November 2010
Academic Editor: Jimmy Yu
Copyright © 2010 Akira Nishimura et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
Hydrogen (H
2
) is normally used as the fuel to power polymer electrolyte fuel cell (PEFC). However, the power generation
performance of PEFC is harmed by the carbon monoxide (CO) in the H
2
that is often produced from methane (CH
4
). The purpose
of this study is to investigate the experimental conditions in order to improve the CO oxidization performance of mesoporous silica
loaded with TiO
2
. The impact of loading ratio of TiO
2
and initial concentration ratio of O
2
to CO on CO oxidization performance
is investigated. As a result, the optimum loading ratio of TiO
2
and initial concentration ratio of O
2
to CO were 20 wt% and 4 vol%,
respectively, under the experimental conditions. Under this optimum experimental condition, the CO in rich H
2
in the reactor can
be completely eliminated from initial 12000 ppmV after UV light illumination of 72 hours.
1. Introduction
Polymer electrolyte fuel cell (PEFC) has been developed
vigorously in the world since it is an attractive and clean
power generation technology. H
2
is normally used as the
fuel to power PEFC. However, the reduction of PEFC
power generation performance has been observed due to the
existence of CO in the H
2
produced from CH
4
, CH
3
OH, and
gasoline.
CH
4
is normally the feedstock to produce H
2
with Ni or
Ru as catalyst at the high temperature range of 873 K–973 K
through the following reaction:
CH
4
+H
2
O -→ CO + 3H
2
. (1)
After this reaction, there is about 10 vol% of CO in the
products. The CO concentration can be reduced down to
about 1 vol% by the following so-called shift reaction:
CO + H
2
O -→ CO
2
+H
2
. (2)
After the shift reaction, the concentration of CO needs
to be further reduced down to 10 ppmV by the following
selective oxidization reaction:
CO +
1
2
O
2
-→ CO
2
. (3)
In the H
2
purification processes mentioned above,
precious metal catalysts and thermal energy are used, and
the processes are costly. An alternative process, that is, using
the TiO
2
photocatalyst combined with adsorbent to oxidize
CO is being developed recently due to its potential cost and
energy saving.
TiO
2
can oxidize CO under illumination of ultraviolet
(UV) ray (available in sunlight) through the following
reaction scheme [1, 2].
Photocatalytic reaction:
TiO
2
+ hv (< 380 nm) -→ h
+
+e
-
. (4)
Oxidization of CO:
CO + h
+
-→ CO
+
. (5)