Nanostructured
metal oxides, such as Cu2O, CeO2, α-Fe2O3, and TiO2, can efficiently
mediate photocatalysis for solar-to-chemical energy conversion and
pollution remediation. In this contribution, we report a novel approach,
dielectric Mie resonance-enhanced photocatalysis, to enhance the catalytic
activity of metal oxide photocatalysts. Specifically, we demonstrate
that Cu2O nanostructures exhibiting dielectric Mie resonances
can exhibit up to an order of magnitude higher photocatalytic rate
as compared with Cu2O nanostructures not exhibiting dielectric
Mie resonances. Our finite-difference time-domain (FDTD) simulation
and experimental results predict a volcano-type relationship between
the photocatalytic rate and the size of Cu2O nanospheres
and nanocubes. Using transient absorption measurements, we reveal
that a coherent electronic process associated with dielectric Mie
resonance-mediated charge carrier generation is dominant in Cu2O nanostructures that exhibit higher photocatalytic rates.
Although we experimentally demonstrate dielectric Mie resonance-enhanced
photocatalysis with only Cu2O nanoparticles here, based
on our FDTD simulations, we anticipate the same can be achieved with
other metal oxide photocatalysts, including CeO2, α-Fe2O3, and TiO2.