Highly efficient chemically-driven micromotors with controlled snowman-like morphology.

We report the synthesis of silver-based Janus micromotors that self-propel at 3.5 μm s-1 and speed up to 45 μm s-1 in 0.044 and 1.5 mM of H2O2, respectively, via ionic diffusiophoresis. Morphology optimization further accelerates the speed to 90 μm s-1, which leads to a force of 1 pN and a power of 0.1 fW, similar to biomolecular motors. Their efficiency reaches 10-5, at least two orders of magnitude higher than other chemically-driven micromotors. These micromotors hold great promises in various applications.