Intrinsic electrochemical performance and precise control of surface porosity of graphene-modified electrodes using the drop-casting technique

• Graphene-modified electrodes do not exhibit discernible thin-layer diffusion.
• Electrode porosity can be controlled close to the case of ideal planar electrodes.
• Multiple aliquots are preferable over a single concentrated coat for drop-casting.
• Graphene flakes remain dispersed when prepared using multiple aliquots.
• Aggregation commonly occurs when concentrated graphene dispersions are used.

Graphenes have for a long time been shown to exhibit enhanced electrochemical sensing and fast heterogeneous electron transfers, but the nature of such improved electrochemistry is disputed due to its inherent porosity. Adsorption and thin layer effects may additionally contribute to the observed behaviour. Furthermore, overall extents of the impact from these factors are typically unclear. Towards a practical solution to this issue, we show that electrode porosity can be adequately controlled close to the case of an ideal planar electrode. With increased mass loadings, the apparent porosity can still be precisely controlled by performing multiple drop-casts from less concentrated dispersions. Thus with application of such experimental practices, the drop-casting technique remains a reliable option for nanomaterial electrode preparation.