Environmental Engineering Reference
In-Depth Information
Low-Cost Nanomaterials
for Photoelectrochemical Water Splitting
Gongming Wang, Xihong Lu and Yat Li
Abstract Hydrogen represents a clean and high gravimetric energy density
chemical fuel that could potentially replace fossil fuels and natural gas in elec-
tricity generation and powering vehicles. Central to the success of hydrogen
technology and economy, the sustainability, efficiency and cost of hydrogen
generation are the major factors. Industrial hydrogen is currently obtained from
steam methane reforming and water-gas shift reaction, however, this method still
relays on fossil fuels. Therefore, it is important to develop efficient, low-cost, and
scalable method to produce hydrogen in a sustainable manner. Photoelectro-
chemical (PEC) water splitting to produce hydrogen is one of most promising and
sustainable approaches. The development of low-cost and efficient nanostructured
photoelectrodes is the key to achieve this goal. In this chapter, we will give a brief
background
on
PEC
water
splitting
and
review
the
recent
advancement
of
developing low-cost nanostructured photoelectrodes.
1 Background of Photoelectrochemical Water Splitting
Photogeneration of hydrogen by water splitting has attracted a lot of attentions,
because water is the most abundant source of hydrogen carrier on the earth [
23
,
25
,
42
,
65
,
89
,
92
,
96
,
105
]. However, water splitting is known to be an uphill reaction:
H
2
O(l)
!
H
2
ðÞ
+ 1/2O
2
ðÞ
DG ¼
237
:
2 KJ/mol
:
This process can be achieved via electrolysis with applied external potentials and a
minimal
potential
of
1.23 V
is
needed
to
drive
this
reaction.
Due
to
the
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