We employed Cyclic-Voltametry (C-V) technique to understand the relative band positions of Fe
2
O
3
and BFO from the oxidation/ reduction potentials. The values of
LUMO (or conduction band) positions were calculated from the reduction potential Vs the internal standard of ferrocene. In a typical experiment, 0.1 M LiCl4 was added in
Acetonitrial to prepare the electrolyte. The C-V measurements were performed with FTO substrate coated with Fe
2
O
3
(or BFO) by doctor blade method as the working electrode, platinum foil as the counter electrode and Ag/AgCl as the reference electrode.
Figure S1 Shows Current-Voltage (I-V) curve for BFO with above mentioned experimental conditions. The calculations for the band position of BFO are as follows,
E
1/2
= 0.37 for ferrocene
E red
(BFO) = - 0.53
E red
= E red
(BFO) - E
1/2
= - 0.53 - 0.37 = - 0.8
E
Lumo
(BFO) = - (E red
(BFO) + 4.8)
E
Lumo
(BFO) = - (- 0.8 + 4.8) = - 4.0 eV

Figure S1 Cyclic voltametry curve for BFO.
Figure S2 shows Current-Voltage (I-V) curve for F
2
O
3
cyclic voltametry measurement and related calculations for Fe
2
O
3 are
E
1/2
= 0.37 for ferrocene
E red
(Fe
2
O
3
) = - 0.18
E red
= E red
( Fe
2
O
3
) - E
1/2
= - 0.18 - 0.37 = - 0.55
E
Lumo
(Fe
2
O
3
) = - (E red
(Fe
2
O
3
+ 4.8)
E
Lumo
( Fe
2
O
3
) = - (- 0.55 + 4.8) = - 4.25 eV

Figure S2 Cyclic Voltametry curve for Fe
2
O
3
Figure S3 shows the Band diagram drawn from the Cyclic Voltametry study,
Figure S3: Relative band diagram for Fe
2
O
3
and BFO the Cyclic Voltametry measurements

0
1
2
4.4 eV 3.3 eV
3
4 e -
E
C e -
5
6
7
E
C
E
V
2.2 eV
2.2 eV
E
V
2.8 eV h +
Visible light a
2
3

2
3 h +
3
Figure S4: Relative band diagram for Fe
2
O
3
and BFO based on reported literature.
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3
/Nb-doped SrTiO
3
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3 nanoparticles with a

-Fe
2
O
3
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