Abstract
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Crystal facet engineering of semiconductor photocatalysts is
regarded as an emerging strategy to tune their physicochemical
properties and optimize the photoreactivity of the materials. In
this work, two plate-like Bi2MoO6 samples were prepared,
dominant in either the distinctly different {100} or {010} facets.
As a consequence of the electronic structure effects induced by
the facets, the {100}-dominant Bi2MoO6 (100-BMO) possessed a
smaller band gap and delivered a much higher photocatalytic
water oxidation activity than {010}-dominant Bi2MoO6 (010-
BMO). A greater charge carrier density in 100-BMO was found
to promote electron accumulation on the {100} surfaces,
leading to the narrower band gap, as supported by Mott-
Schottky measurements. Efficient intrinsic electron-hole separation
and longer charge carrier lifetimes in 100-BMO were also
observed. Further, a higher photocurrent density and smaller
Nyquist plot arc radius presented by 100-BMO imply a higher
charge transfer capacity. EPR analysis indicated that the 100-
BMO boasted a higher oxygen vacancy density, whereby the
vacancies could serve as shallow donors to trap electrons and
suppress photogenerated electron-hole pair recombination.
Overall, the {100} facet in Bi2MoO6 delivered a mix of distinctly
advantageous characteristics relative to the {010} facet with the
findings clearly illustrating the value of crystal facet engineering
in boosting photocatalytic performance.