(491d) Synthesis of Functional Nanostructured TiO2 Photo Active Membranes for Room Temperature Water Splitting | AIChE

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(491d) Synthesis of Functional Nanostructured TiO2 Photo Active Membranes for Room Temperature Water Splitting

Authors 

Kawde, A. Y. - Presenter, South Dakota School of Mines & Technology
Vats, A. - Presenter, South Dakota School of Mines and Technology
Puszynski, J. A. - Presenter, South Dakota School of Mines & Technology
Shende, R. - Presenter, South Dakota School of Mines and Technology


Photo assisted splitting of water at room
temperature to produce hydrogen on a liquid-semiconductor (L-S) interface holds
great technological importance toward hydrogen economy. In order to
electrochemically split water into H2 and O2,
thermodynamic electrochemical potential (E0) of 1.23 V (Vs NHE) is
required, where Ereduction is at 0 V(Vs NHE) for H2 half
cell reaction (2H+ + 2e- àH2) and Eoxidation is -1.23 V(Vs
NHE) for O2 half cell reaction (2OH- à 2H+ + 2e-+ O2).
The above reactions occurs preferentially on a L-S interface under solar
radiation. Various semiconductors such as CdS, InP, SiC, Si, TiO2,
Ta2O3, Fe2O3 and SrTiO3
have been studied as a potential photo-catalyst for photolysis of water.
However, majority of these materials have shown a poor stability to photo
oxidative corrosion with TiO2 being an exception. TiO2 is
a broadband semiconductor with Eg ~ 3.1eV (UV) and a relatively poor
electronic conductor. However, its electronic properties can be improved by
controlling its shape and chemical composition. This contribution focuses on
the synthesis and application of specific TiO2 based functional nanostructures
in a form of a membrane for photo assisted water splitting application. The
proposed functional membrane structure has an advantage over the conventional
approach i.e. colloidal TiO2. In the present work, an attempt has
been made to take advantage of superior directional electronic transport in TiO2
nanotubes (nt-TiO2). Under this approach, an nt-TiO2/Ti/nt-TiO2
membrane structure was synthesized using electrochemical anodization in fluorine
(F-) based electrolyte. Further, this nt-TiO2/Ti/nt-TiO2
membrane structure was modified by preferential deposition of Pt and RuO2
co-catalysts on either side of the membrane. The selective placement of Pt and
RuO2 on nt-TiO2/Ti/nt-TiO2 membrane structure could prove to be beneficial
to achieve physical separation of H2 and O2 in a water
photolysis reactor utilizing a single electrode scheme.   

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