Laser-induced highly oriented pyrolytic graphite for high-performance screen-printed electrodes†
Screen-printed carbon electrodes (SPCEs) are enjoying increasing popularity in different electrochemistry areas, from electroanalysis to energy storage and power generation. Highly oriented pyrolytic graphite (HOPG), an ordered form of graphite, displays excellent electrochemical properties. However, its application in screen-printed electrodes has remained elusive. In this work, we present a straightforward laser-based process to selectively transform, in ambient conditions, the surface of conventional SPCEs into highly homogeneous HOPG. Energy densities between 6.8 and 7.7 mJ cm−2 result in a binder-free, high-purity HOPG surface with very fast electron transfer rates. The electrode transformation to HOPG has been followed by SEM, Raman spectroscopy and XPS. Cyclic voltammetry of model systems ferrocyanide, ferrocenecarboxylic acid, dopamine and hydroquinone has been used to determine variations in electrode kinetics (from 50% increase for ferrocenecarboxylic acid, up to ca. 2 orders of magnitude for ferrocyanide and dopamine) and interfacial capacitance (from 40 up to 220 μF cm−2). Finally, differential pulse voltammetry (DPV) has been used to demonstrate the ability of these electrodes to detect dopamine in the presence of an excess amount of ascorbic acid.