Manganese Oxide-Based Chemically Powered Micromotors

Chemically powered micromotors represent
an exciting research area in nanotechnology. Such artificial devices
are typically driven by catalytic bubble formation, taking place at
the solid–liquid interface. Platinum has been most frequently
used for the fabrication of different micromotors due to its superior
catalytic efficiency. Other materials typically suffer from slow speeds
and require very high concentrations of chemical fuel. Here, we report
preparation and characterization of fast moving micromotors based
on manganese oxide (MnO2) with different geometrical shapes
(tubes, rods, and spheres). On the basis of the results, the prepared
micromotors reached the highest speeds (up to ∼900 μm
s–1 in 10% H2O2) reported
to date for any MnO2-based micromotors. Moreover, they
moved by bubble propulsion even at very low concentrations of peroxide
fuel. Thus, MnO2 represents a promising material for the
preparation of micromotors for various biomedical or environmental
applications, where high speeds are desired.