(511c) Studies On Nanostructured Bilayered Semiconductor System in PEC Water Splitting for Hydrogen Production

Studies
on Nanostructured Bilayered Semiconductor System in PEC Water Splitting for
Hydrogen Production

Surbhi Choudhary¹,
Sumant Upadhyay¹, Pushpendra Kumar¹, Nirupama Singh¹,
Vibha
R. Satsangi², Rohit Shrivastav¹ and
Sahab Dass¹*

¹Department of
Chemistry, Faculty of Science, Dayalbagh Educational Institute, Agra-282110
(India)

²Department of Physics
& Computer Sciences, Faculty of Science, Dayalbagh Educational Institute,
Agra-282110 (India)

Performance of
photo-electrodes in photoelectrochemical (PEC) water splitting
for hydrogen production can be improved by fabricating bilayered electrodes
consisting of two
semiconductors possessing different energy levels for their corresponding conduction and valence band. The small/mid band gap
semiconductor is primarily responsible for visible light absorption and
sensitizing the large band gap semiconductor through electron and/or hole
injection. The
energy layers in the bilayered semiconductors can cover visible spectrum
thereby offering synergistic effect and better output.

In the present study, an attempt has been
made to synthesize bilayered SrTiO₃ (~3.5 eV) / WO₃ (~2.7eV)
thin films by sol-gel spin-coating process on conducting glass substrate to explore its
application in PEC cell.
Prepared thin films were characterized for: (a) crystalline phase by XRD
analysis, (b) band gap energy by spectrometric measurement and (c) surface
morphology by SEM analysis. Subsequently, SrTiO₃/WO₃
bilayered film was used in a PEC cell as working electrode having platinum and saturated
calomel as counter and reference electrode respectively and 150 W Xenon lamp as
light source for illumination. Maximum photocurrent density 0.091 mA/cm² at 0
V/SCE was observed for bilayered
SrTiO₃/WO₃ thin film photoelectrode which
was two folds higher than offered by SrTiO₃ (0.046
mA/cm²) and much higher than that for WO₃ thin films [Fig. 1]. The enhanced photoelectrochemical behaviour of
bilayered photoelectrodes can be attributed to: (a) the extended absorption towards
visible region, (b) formation of mixed oxide at the interface and (c) enhanced
charge separation of both the materials resulting in decrease of recombination
of charge carriers.

Keywords: Photoelectrochemical cell, Heterojunction,
Solar energy, Water splitting

*Corresponding
author:
Sahab Dass

 
Email: drsahabdas@gmail.com