Electrochemical characteristic assessments toward 2,4,6-trinitrotoluene using anodic TiO2 nanotube arrays

Abstract

The feasibility of electrochemical detection of 2,4,6-trinitrotoluene (2,4,6-TNT) using TiO2 nanotubes synthesized through electrochemical anodization of Ti was explored. TiO2 nanotube arrays with distinctly different surface features, including an initiation layer and tube wall structures, were prepared, and the efficacy for the electrochemical reduction of 2,4,6-TNT was comparatively evaluated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The electrochemical sensing properties of the anodic TiO2 nanotubes were not affected by the surface morphology based on the different anodization conditions. The mechanism governing the mass transfer of 2,4,6-TNT during electrochemical reduction was dominated by diffusion, as determined based on LSV analyses at various scan rates. Importantly, the TiO2 nanotube arrays can distinguish 2,4,6-TNT and cyclotrimethylenetrinitramine (RDX) in mixture solutions of 2,4,6-TNT, RDX, and pentaerythritol tetranitrate (PETN), with four distinct reduction peaks in the voltammogram. Further studies are needed to enhance the efficacy of the TiO2 nanotube arrays for the electrochemical reduction of explosive compounds, where introducing metal dopants, quantum dots, or vacancy engineering are prospectively effective strategies.