Measuring the Electrochemical Response of a Titanium Dioxide Nanotube Electrode to Various Chemicals as Explosive Components
Samuel C. Johnson
Department of Mechanical Engineering, California State Polytechnic University-Pomona, 3801 W Temple Avenue, Pomona, CA 91768, USA
Yong X. Gan *
Department of Mechanical Engineering, California State Polytechnic University-Pomona, 3801 W Temple Avenue, Pomona, CA 91768, USA
Sinclair B. Calderon
Department of Mechanical Engineering, California State Polytechnic University-Pomona, 3801 W Temple Avenue, Pomona, CA 91768, USA
James L. Smith
Department of Chemistry, University of Rhode Island, Kingston, RI 02881, USA
Jimmie C. Oxley
Department of Chemistry, University of Rhode Island, Kingston, RI 02881, USA
*Author to whom correspondence should be addressed.
Abstract
Sensing and mitigating explosives are critical for homeland security. This paper investigates the electrochemical responses of TiO2 nanotubes exposed to several chemicals including ammonium nitrate, hydrogen peroxide, methanol, ethanol and ethylene glycol which are used directly as explosives, or as the starting materials for making explosives. Cyclic voltammetry (CV) tests were performed to identify the characteristics of these chemicals at the surface of the TiO2 nanotube electrode. It is found that the trends for system responses to methanol, ethanol and hydrogen peroxide reveal the oxidation of these chemicals in the low voltage range from 0 V to 0.3 V. For ammonium nitrate, the hysteresis of the CV loops covers a much bigger potential range from 0.1 V to 0.8 V. The ethylene glycol shows the mass transfer controlling response which is due to the high viscosity of the solution.
Keywords: Titanium oxide nanotube, electrochemistry, cyclic voltammetry, surface reactions, explosive detection and mitigation