Phenosafranine encapsulated mesoporous silica as efficient electrocatalyst for Cr(VI) reduction and its subsequent sensitive determination

Abstract

This work presents an easy, highly specific, and sensitive route for the electrochemical reduction of Cr(VI) by phenosafranine (PSF+) integrated sulfonic acid functionalized mesoporous silica microspheres (MS-SO3−), denoted as PSF+-MS-SO3−. The synthesized material is characterized using various spectroscopic and microscopic methods. The glassy carbon electrode (GCE) is modified with this material (represented as GCE/PSF+-MS-SO3−) and employed for electroanalytical applications. The electrochemical characteristics of PSF+-MS-SO3− are established by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Further, it is exploited for the electrocatalytic reduction of, Cr(VI). Superior electron transfer kinetics and stable electrochemical response for Cr(VI) are observed at the GCE/PSF+-MS-SO3− electrode. Moreover, the quantitative estimation of Cr(VI) at the GCE/PSF+-MS-SO3− done using linear sweep voltammetry (LSV). Dual linear calibration ranges (1 to 20 µM and 20 to 100 µM) is obtained from the LSV response. A low limit of detection (0.5 µM) and superior sensitivity (1.1 µA µM−1 cm−2) are recognized at this electrode. In addition, significant selectivity in the existence of other interfering ions is also shown by fabricated sensing scaffold. The precise measurement of Cr(VI) in spiked water samples with simple matrix is also demonstrated successfully with sufficient durability and reproducibility.