  2D layered ferroelectric materials such as CuInP$_2$S6 (CIPS) are promising
candidates for novel and high-performance photocatalysts, owning to their
ultrathin layer thickness, strong interlayer coupling, and intrinsic
spontaneous polarization, while how to control the photocatalytic activity in
layered CIPS remains unexplored. In this work, we report for the first time the
photocatalytic activity of ferroelectric CIPS for the chemical deposition of
silver nanostructures (AgNSs). The results show that the shape and spatial
distribution of AgNSs on CIPS are tunable by controlling layer thickness,
environmental temperature, and light wavelength. The ferroelectric polarization
in CIPS plays a critical role in tunable AgNS photodeposition, as evidenced by
layer thickness and temperature dependence experiments. We further reveal that
AgNS photodeposition process starts from the active site creation, selective
nanoparticle nucleation/aggregation, to the continuous film formation.
Moreover, AgNS/CIPS heterostructures prepared by photodeposition exhibit
excellent resistance switching behavior and good surface enhancement Raman
Scattering activity. Our findings provide new insight into the photocatalytic
activity of layered ferroelectrics and offer a new material platform for
advanced functional device applications in smart memristors and enhanced
chemical sensors.
