Green Synthesis of Single-Crystalline Akaganeite Nanorods for Peroxidase Mimic Colorimetric Sensing of Ultralow-Level Vitamin B1 and Sulfide Ions

Development of low-cost nanomaterials for ultralow-level molecular sensing applications is drawing significant attention. In this report, single-crystalline akaganeite (β-FeOOH) nanorods were synthesized at room temperature in aqueous medium by green protocol using tea extract for sensing applications. Microscopic investigation revealed the dimensions of nanorods are 150 ± 20 nm in length and 35 ± 10 nm in diameter. The concentration of tea extract plays a crucial role on the final shape of the nanostructure. As-synthesized β-FeOOH nanorods exhibit good peroxidase-like activity in the presence of H2O2. The synthesized β-FeOOH nanorods were tested for a rapid colorimetric detection of thiamine (vitamin B1), H2O2, and S2– ions in the aqueous solutions. The sensitivity of this colorimetric probe to thiamine and S2– ions was excellent with a limit of detection as low as 44 nM and 2.19 μM, respectively. This work provides an efficient, green, reproducible, and economical approach to synthesize rodlike β-FeOOH nanostructures for sensor applications.