Catalytic Micropumps:Microscopic Convective Fluid Flow and Pattern Formation

摘要

Scaling a chemistry laboratory down to microchip size is one of the driving forces for developing microanofluidics.Engineering fluid flows at this scale remains an interesting challenge.Flow can be driven by externally applied pressure,electric fields,thermal or concentration gradients.Heterogeneous catalysis offers a new and potentially powerful alternative.Energy from a "fuel" can be converted locally at a catalyst surface,possibly eliminating external pumps or power sources.We previously reported the autonomous movement of platinum-gold nanorods and micro-gears in dilute solutions of H_2O_2.By Galilean invariance,one should expect immobilized catalytic objects to generate flow in the surrounding fluid,with similar scaling of device size and fluid velocity.Here,we describe pattern formation and convective fluid flow at the microscale induced by the bipolar electrocatalytic decomposition of hydrogen peroxide.