Unexpectedly, oxygen plasma treatment also enhances the electron transfer rate. Our hypothesis is that partial etching of the LIG-E material or the presence of contaminants increases the number of exposed graphenic edges, which in turn facilitates interfacial reaction kinetics . Compared to other systems, the rate constant values reported here (k0 ~ 0.01 cm s -1 ) are approximately one order of magnitude higher than those fabricated by carbon screen printing and conventional laser pyrolyzation, but lower than the laser-pyrolized polyimide (Table ) .