Chemical nature of electrochemical activation of carbon electrodes.

Electrochemical activation of carbonaceous electrodes is a common step in the preparation of high-performance electrochemical (bio-)sensors. The underlying mechanism has long been discussed but is, however, not yet fully understood. Here, we propose that electrochemical activation can produce graphene derivatives that largely enhance the electrochemical performance of carbonaceous electrodes using a carbon paste electrode or a carbon rod electrode as samples. Based on morphological, chemical and electrochemical evidence, we conclude that in the electrochemical activation of carbonaceous electrodes, graphene oxide or reduced graphene oxide could be generated in situ, which is the main reason for the enhancement of the electrode performance. Moreover, chemical and biological sensors made from electrochemically activated carbonaceous electrodes resemble their counterparts made from chemically prepared graphene-derivative-modified carbonaceous electrodes and even exhibit better performance. These findings could enable us to establish an efficient and predictable solution for graphene-related electrochemistry and surface chemistry.