The combination of the piezoelectric effect and photoexcitation
properties in ferroelectric/piezoelectric materials used for piezo-photocatalysis
is one of the current research hotspots in the field of sewage treatment
and environmental remediation. Lead-free ferroelectric BaTi2O5 (BT2) exhibits a strong photoexcitation response and
is strongly piezoelectric, so it shows excellent promise as an effective
piezo-photocatalyst. Herein, a molten salt method was adopted to prepare
a 1D BT2 nanorod with different average aspect ratios, which have
been used as piezo-photocatalysts for the first time. The as-prepared
BT2 nanorods had an excellent piezoelectric response, as determined
by piezo-response force microscopy. The optimal BT2 nanorods were
able to piezo-photocatalytically degrade rhodamine B (RhB) with excellent
performance. Under ultrasonication and visible-light coexcitation,
this catalyst achieved the highest first-order rate constant of k = 0.0353 min–1, 4.24 times higher than
the rate constant achieved with ultrasonic excitation alone and 5.42
times higher than that achieved under visible-light irradiation alone.
Moreover, the best degradation effect for the removal of quinolones
[levofloxacin (LEV)] and other organic pollutants (methylene blue
and methyl orange) was also achieved by the BT2 nanorods under ultrasonication
and visible-light coexcitation. The internal piezoelectric field caused
by bending vibration deflected the photogenerated carriers to the
radial direction, which originally flowed toward the ends of the nanorods.
This increased the participation of carriers at the active sites and
reduced their migration distance. Therefore, the recombination of
photogenerated carriers was inhibited, and better piezo-photocatalytic
performance for pollutant degradation was achieved. The strong correlation
between piezoelectric properties and the coupling effect of piezoelectric-photocatalysis
is demonstrated by this work, which offers a strategy to optimize
the flow of photogenerated charge carriers in one-dimensional (1D)
photocatalysts and, in turn, improve the photocatalytic efficiency
of 1D photocatalysts for the degradation of organic pollutants.