Chemical-bath-deposited rutile TiO2 film for electrochemical detection of 2,4,6-trinitrotoluene

Abstract

In this study, 2,4,6-trinitrotoluene (2,4,6-TNT) was detected electrochemically through cyclic voltammetry (CV) and differential pulse voltammetry (DPV) by using a rutile TiO2 layer under ambient conditions. To accomplish this, an electrode was fabricated in a short time by using the chemical bath deposition process under low-temperature conditions. A rutile TiO2 layer was grown on both fluorine-doped tin oxide and glass surfaces by using a precursor solution containing chloride ions. Following calcination, the crystallinity of the rutile phases in the TiO2 layer was enhanced. In the CV profiles (obtained over a potential range between −0.6 and −1.2 V (versus Ag/AgCl, 3 M KCl) in a 100 ppm 2,4,6-TNT solution under ambient conditions), the three main reduction peaks of 2,4,6-TNT were observed only for the calcined TiO2 layer owing to the increased crystallinity of the rutile phase and the increased active site density. Calcination facilitated high active site density, a large electrochemically active surface area, and short electrochemical reaction times under low charge transfer resistance, which were key for enhancing the performance of the rutile TiO2 layer as the electrode toward 2,4,6-TNT detection. The DPV results revealed that the limits of detection and quantitation were 10.8 ppm and 36.0 ppm, respectively, with a linear range of 10–100 ppm, for 2,4,6-TNT detection using the calcined TiO2 layer as the working electrode. The detection of 2,4,6-TNT using a crystallized transition metal without a noble metal support is an attractive approach that can be applied toward the detection of other explosive nitro-organic compounds such as nitroglycerin and pentaerythritol tetranitrate.