Nanoscale engineering to control mass transfer on carbon-based electrodes

Abstract

Here we use an electrode consisting of carbon nanofibers (CNFs), the lengths and surface population density of which can be effectively controlled. It is shown that (i) a thin liquid layer forms when the thickness of the diffusion layer has a specific ratio to the dimensions of the nanostructured carbon surface. (ii) This leads to a decrease in the peak potential difference and a subsequent increase in the apparent heterogeneous electron transfer (HET) constant, both of which could be interpreted as a result of increased catalytic activity. (iii) However, we show that this explanation is not likely, as our materials are chemically identical, and we use an outer sphere redox (OSR) probe to minimize any specific chemical interactions. On the contrary, (iv) the results clearly show that the observed behavior is caused by a combination of the formation of a thin liquid layer and the increased apparent surface area of the electrodes.