Chemical-Assisted Mechanical Lapping of Thin Boron-Doped Diamond Films: A Fast Route Toward High Electrochemical Performance for Sensing Devices

Abstract

There is an urgent need for an effective and economically viable increase in electrochemical performance of boron-doped diamond (BDD) electrodes that are used in sensing and electrocatalytic applications. Specifically, one must take into consideration the electrode heterogeneity due to nonhomogenous boron-dopant distribution and the removal of sp2 carbon impurities saturating the electrode, without interference in material integrity. In this work, authors describe a detailed study on electrochemical performance and the enhancement of electrochemical active surface area in the BDD electrodes that have been pretreated via chemical-assisted mechanical lapping.The effect of lapping on both surface chemistry and oxidation processes at the BDD surface was assessed by means of chronovoltammetry, instantaneous impedance monitoring, and X-Ray photoelectron spectroscopy. Next, atomic force microscopy and scanning electron microscopy were employed to produce data on spreading resistance and surface geometry, respectively.While the analyzed interactions are very complex and multi-level, authors suggested that the main observed effect was due to the removal of non-diamond carbon impurities from the electrode surface, decreased grain size, and heterogeneous conductivity. Short-duration pretreatments were found to be an effective route towards more efficient surface activation with negligible alterations in the diamond film structure. A prolonged pretreatment led to a decrease in grain size and lowered contribution of (111) and (110) facets, which in turn influenced the electrode kinetics.