Microgravity Effects of Nanoscale Mixing on Diffusion Limited Processes Using Electrochemical Electrodes

This proposal is for a study of the microgravity effects on nanoscale mixing of a diffusion limited process using electrochemical electrodes. In previous research by Micro-G CANM 1, the electrochemical oxidation of ammonia in microgravity conditions was utilized as the means to characterize a variety of nanomaterials according to their catalytic activity. The results of these parabolic aircraft experiments led to the measurement of a 20-65% decrease in the catalytic current under microgravity. This reduction in catalytic current is hypothesized to occur due to the lack of buoyancy driven mixing at the solution-electrode interface. It is believed that this effect is influenced by the pore size and structure of the material. This lack of buoyancy driven mixing at the solution-electrode interface may be addressed by employing hydrodynamic turbulent mixing and by the reengineering of the electrode geometry and pore structure. The objective to this proposal is to test these mitigation approaches and develop a better understanding of this phenomenon. Specifically, this proposal will evaluate the effect on electrode performance by: employing hydrodynamic turbulence at different flow rates towards a platinum catalyst electrodeposited on a glassy carbon electrode, changing the electrode structure by utilizing bulk electrolysis, and changing the pore size by the utilization of three different mesoporous carbon supports with average diameters of 64, 100, and 137. More »