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RSC Advances
between ZnIn-MMO and g-C3N4 could facilitate the efficient
transportation and separation of the photogenerated charge
carriers in composite under visible light irradiation. Further-
more, the heterostructure improved the stability of the ZnIn-
MMO nanoparticles on the surface of the g-C3N4 sheets. The
as-synthesized g-C3N4–based photocatalyst composites can be
regarded as a sort of promising material for further applications
in advanced oxidation process utilizing visible light.
Fig. 13 Proposed mechanism of charge separation and photocatalytic
activity over ZnIn-MMO/g-C3N4 photocatalyst under visible light
irradiation.
Acknowledgements
We thank gratefully the nancial support from 973 Program
(2011CBA00506), National Natural Science Foundation of China
and Program of Beijing Engineering Center for Hierarchical
Catalysts.
of In2O3 can conveniently transfer to the VB of g-C3N4. On the
other hand, due to the wide band gap, ZnO cannot be excited
under visible light irradiation. However, ZnO nanocrystallites in
contact with In2O3 components can act as electron traps facil-
itating the electron–hole separation. Namely, the photo-
generated electrons can easily migrate to the surface of ZnO. As
a result, the above charge transfer may reduce the recombina-
tion of the photogenerated electrons and holes of and greatly
increase the photocatalytic activity of ZnIn-MMO/g-C3N4 pho-
tocatalysts. This efficient separation of photogenerated elec-
tron–hole pairs driven by band potentials between g-C3N4, ZnO
and In2O3 semiconductors is not reported until now.
Notes and references
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In the course of photocatalytic degradation of dyes, the
electrons on ZnO can be scavenged by the adsorbed molecular
O2 to yield the superoxide radical anion cO2ꢀ, due to more
negative reduction potentials of g-C3N4, In2O3 and ZnO,
ꢀ
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4. Conclusions
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RSC Adv., 2015, 5, 5725–5734 | 5733