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Charge Coupling Enhanced Photocatalytic Activity of BaTiO3/MoO3 Heterostructures
journal contribution
posted on 2019-10-15, 19:16 authored by Kevin V. Alex, Aarya Prabhakaran, A. R. Jayakrishnan, K. Kamakshi, J. P. B. Silva, K. C. SekharIn this work, we
proposed an efficient heterostructure photocatalyst by integrating
the ferroelectric BaTiO3 (BTO) layer with the semiconductor
MoO3 layer, availing the ferroelectric polarization of
BaTiO3 and high generation of photoinduced charge carriers
in the MoO3 layer. The effect of MoO3 layer
thickness (tMoO3) on the photocatalytic
efficiency of the BTO/MoO3 heterostructures is found to
be optimum at tMoO3 = 67 nm
as tMoO3 varies from 40 to
800 nm. The BTO/MoO3 heterostructure with tMoO3 = 67 nm exhibits a high efficiency of
86% for the degradation of rhodamine B (RhB) under the exposure of
UV–visible light for 60 min. The photocatalysis rate kinetics
analysis reveals that the rate constant in the heterostructure is
1.7 times of pure BTO and 3.2 times of pure MoO3 films.
The enhanced photocatalytic activity in the heterostructures is attributed
to the electric field-driven carrier separation due to the ferroelectric
polarization and the heterojunction band bending. The charge coupling
effect between BaTiO3 and MoO3 is evident from
the current–voltage characteristics. The maximum lattice strain
in the heterostructure with tMoO3 = 67 nm as evident from X-ray diffraction (XRD), Fourier transform
infrared spectroscopy (FTIR), and photoluminescence (PL) analysis
further confirms the charge transfer between the layers. The degradation
as well as decolorization efficiency of the BTO/MoO3 heterostructure
is higher than that of pure BTO and MoO3 films. Radical
trapping experiments reveal that electrons are the major contributors
to the photocatalytic activity of the BTO/MoO3 heterostructure.
The reusability test shows only a reduction of 5% in the efficiency
of the heterostructure after five photocatalysis cycles. The heterostructure
can also efficiently decompose the other dyes such as rose bengal
and methyl violet. Thus, our findings prove that an efficient and
reusable photocatalyst can be designed through the integration of
the ferroelectrics with the semiconductor layers.