Increasing the Electric Double‐Layer Capacitance in Boron‐Doped Diamond Electrodes

Abstract

Highly boron-doped diamond (BDD) electrodes containing sp 2 carbon impurities exhibit an increase in the electric doublelayer capacitance (C dl ) after anodic oxidation. Although it is known that the electrochemical properties of BDD electrodes are affected by several factors, including the boron concentration, the amount of sp 2 carbon impurity, and the surface termination and orientation, clarification of the mechanism for the increase in C dl needs to be done. To this end, we prepared several BDD samples under various conditions and the properties of these samples, including C dl , were systematically investigated. The mechanism for the increase in C dl in particular, including the effect of the surface termination, is discussed.

Interrogating the Surface Intermediates and Water Oxidation Products of Boron‐Doped Diamond Electrodes with Scanning Electrochemical Microscopy

“…2.5 V while the surface charge in pH 11 increases to a steady value after ca. 2.7 V. We suspect that holding the BDD at positive potentials for extended periods of time tends to oxidize the surface and change the surface chemistry, potentially generating more active sites for binding intermediates or slowly etching sp 2 regions, leading to increased surface area and thus greater surface charges that are titrated at higher potentials.…”

Unusual Electrochemical Properties of Low-Doped Boron-Doped Diamond Electrodes Containing sp2 Carbon

“…To compare the relative amounts of sp 2 carbon in the different BDD samples, the ratio between the intensities of the G band (around 1530 cm −1 ) and the diamond band (1332 cm −1 for 1% BDDs and 1329 cm −1 for 0.1% BDDs) was calculated using Igor software. 20 This ratio is labeled I G /I Diamond , and the values are given in Table 1. Note that the I G /I Diamond ratio is a qualitative value, not an actual one.…”

“…Also, highly doped BDD with sp 2 is a promising material for capacitors. 19,20 However, usually sp 2 carbon species in BDD electrodes are considered to be defects or impurities, introduced during the growth process. 4 Generally, BDD containing sp 2 carbon is considered to be lowquality diamond, since, when used as an electrode, it has greater background current 15 and more easily corrodes 21 than high-quality (sp 3 ) diamond.…”

“…In some specific applications, such as ozone production, reduction of concentrated hypochlorite in wastewater, electrochemical disinfection, and sensors for dissolved oxygen and for measuring pH, BDD electrodes containing sp 2 outperform other electrodes. Also, highly doped BDD with sp 2 is a promising material for capacitors. , However, usually sp 2 carbon species in BDD electrodes are considered to be defects or impurities, introduced during the growth process . Generally, BDD containing sp 2 carbon is considered to be low-quality diamond, since, when used as an electrode, it has greater background current and more easily corrodes than high-quality (sp 3 ) diamond.…”

Nanodiamond Coating Improves the Sensitivity and Antifouling Properties of Carbon Fiber Microelectrodes

“…The background current is proportional to specific capacitance of the electrode material and electroactive surface area. 55 Although the sp 2 surface groups can increase the capacitance of BDD, 56,57 the 15 and 60 nm ND particles do not fully coat the surface, so they might not add much material for charging. The 5 nm particles actually show slightly decreased capacitance despite the fact they formed thicker coatings, implying the sp 3 -hybridized ND exhibits a slightly lower capacitance that CFMEs.…”