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High Pressure High Temperature Synthesis of Highly Boron Doped Diamond Microparticles and Porous Electrodes for Electrochemical Applications

preprint
submitted on 07.07.2020 and posted on 08.07.2020 by Georgia Wood, Mark Newton, Viacheslav Shkirskiy, Patrick R. Unwin, Julie Macpherson, Mark Munday, Carmen Walters

High pressure high temperature (HPHT) synthesis of crystallographically well-defined boron doped diamond (BDD) microparticles, suitable for electrochemical applications and using the lowest P and T (5.5 GPa and 1200°C) growth conditions to date, is reported. This is aided through the use of a metal (Fe-Ni) carbide forming catalyst and an aluminum dibromide (AlB2) boron source. The latter also acts as a nitrogen sequester, to reduce boron-nitrogen charge compensation effects. Raman microscopy and electrochemical measurements on individual microparticles reveal they are suitably doped to be considered metallic-like and contain negligible sp2 bonded carbon. A compaction process is used to create macroscopic porous electrodes from the BDD microparticles. Voltammetric analysis of the one-electron reduction of Ru(NH3)63+ reveals large capacitive and resistive components to the current-voltage curves, originating from solution trapped within the porous material. Scanning electrochemical cell microscopy (SECCM) is employed to map the local electrochemical activity and porosity at the micron scale. These electrodes retain the advantageous properties of polycrystalline BDD grown by chemical vapor deposition, such as large aqueous solvent window and resistance to corrosion, but with the additional benefits of a high, electrochemically accessible, surface area.

Funding

EP/L015315/1

History

Email Address of Submitting Author

j.macpherson@warwick.ac.uk

Institution

University Of Warwick

Country

United Kingdom

ORCID For Submitting Author

0000-0002-4249-8383

Declaration of Conflict of Interest

no conflict of interest

Exports