  Self-propelled particles and, in particular, those based on mesoporous
silica, have raised considerable interest due to their potential applications
in the environmental and biomedical fields thanks to their biocompatibility,
tunable surface chemistry and large porosity. Although spherical particles have
been widely used to fabricate nano- and micromotors, not much attention has
been paid to other geometries, such as nanorods. Here, we report the
fabrication of self-propelled mesoporous silica nanorods (MSNRs) that move by
the catalytic decomposition of hydrogen peroxide by a sputtered Pt layer, Fe2O3
nanoparticles grown within the mesopores, or the synergistic combination of
both. We show that motion can occur in two distinct sub-populations
characterized by two different motion dynamics, namely enhanced diffusion or
directional propulsion, especially when both catalysts are used. These results
open up the possibility of using MSNRs as chassis for the fabrication of
self-propelled particles for the environmental or biomedical fields.
