Assessment of Boron Doped Diamond Electrode Quality and Application to <em>In Situ</em> Modification of Local pH by Water Electrolysis

Abstract

Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended solvent window, low background currents, corrosion resistance, etc., arise from the catalytically inert nature of the surface. However, if during the growth process, non-diamond-carbon (NDC) becomes incorporated into the electrode matrix, the electrochemical properties will change as the surface becomes more catalytically active. As such it is important that the electrochemist is aware of the quality and resulting key electrochemical properties of the BDD electrode prior to use. This paper describes a series of characterization steps, including Raman microscopy, capacitance, solvent window and redox electrochemistry, to ascertain whether the BDD electrode contains negligible NDC i.e. negligible sp 2 carbon. One application is highlighted which takes advantage of the catalytically inert and corrosion resistant nature of an NDC-free surface i.e. stable and quantifiable local proton and hydroxide production due to water electrolysis at a BDD electrode. An approach to measuring the local pH change induced by water electrolysis using iridium oxide coated BDD electrodes is also described in detail. Video LinkThe video component of this article can be found at

Electrochemical decarboxylation of acetic acid on boron-doped diamond and platinum-functionalised electrodes for pyrolysis-oil treatment

“…35 Surface cleaning prior to electrochemical testing was performed by washing with Milli-Q water (18.2 MΩ cm) and isopropanol, prior to ultrasonication in Milli-Q water for 10 minutes, anodic polarisation in 1 M HClO 4 for 30 minutes and subsequent rinsing with Milli-Q water, following a protocol reported in the literature. 36 For comparison, graphite (LFYGY Industry Materials Professional Supplier, China), FTO (redox.me, Sweden) and nickel foam (IKA, Germany) electrodes were used as both electrodes and substrates. Prior to use, the graphite was polished with carbide paper and sonicated for 10 minutes in Milli-Q water.…”

In-house vs. commercial boron-doped diamond electrodes for electrochemical degradation of water pollutants: A critical review

“…Relevant presence of sp 2 carbon in the BDD films may induce voltametric responses like glassy carbon and graphite (He et al, 2019). The substantial presence of NDC in the grain boundaries of the diamond film causes lower electrode stability when under anodic polarization and, ultimately, the disintegration of the electrode (Read and Macpherson, 2016). The NDC content is also related to higher background current and double-layer capacitance (Bennett et al, 2004).…”