Electrochemical impedance spectroscopy of oxidized and hydrogen-terminated nitrogen-induced conductive ultrananocrystalline diamond

Autor:	Martin Stutzmann, Dieter M. Gruen, Jose A. Garrido, Simon Q. Lud, P. Bruno, Jorge Hernando
Rok vydání:	2009
Předmět:	Materials science Hydrogen Constant phase element General Chemical Engineering Analytical chemistry Diamond chemistry.chemical_element engineering.material Dielectric spectroscopy chemistry Electrode Electrochemistry engineering Grain boundary Composite material Electrical impedance Carbon
Zdroj:	Electrochimica Acta. 54:1909-1915
ISSN:	0013-4686
Popis:	We have studied the electrochemical impedance spectroscopy of conductive ultrananocrystalline diamond (UNCD) modified by either oxidation or hydrogenation surface treatments. The impedance was measured in the frequency range from 0.1 Hz to 40 kHz at different DC voltages and the results fitted to an equivalent electrical circuit. Despite the complexity of the conductive UNCD surface, composed of sp 3 -bonded grains and grain boundaries with a high content of sp 2 -bonded carbon atoms, a Randles circuit with a constant phase element (CPE) for the capacitive element provided a reasonable model for both terminations. However, the parameters of the CPE were very different for each termination. Taking into account the results obtained, we propose that the interfacial impedance of oxidized UNCD is dominated by the oxidized sp 2 -bonded carbon atoms present at the grain boundaries, and the interfacial impedance of hydrogen-terminated UNCD is governed by both the grain boundaries and the grains.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::ca7d538e715ba1352216958cfb84efec https://doi.org/10.1016/j.electacta.2008.10.041 Zobrazit plný text záznamu Full Text from ScienceDirect