Rare earth erbium molybdate nanoflakes decorated functionalized carbon nanofibers: An affordable and potential catalytic platform for the electrooxidation of phenothiazine

Currently, the sonochemical synthesis method has received considerable attention due to its cost-effectiveness, simplicity, and ease of operation compared to other conventional synthesis methods. Significantly, rare earth metal-doped molybdates are promising materials in the fields of photo- and electrochemical detection. Herein, a flake-like structured erbium molybdate (Er₂MoO₆)/functionalized carbon black (f-CNF) composite was synthesized via a facile sonochemical synthesis method. The resultant materials were characterized through spectrophotometric techniques, and the f-CNF/Er₂MoO₆-modified screen-printed electrode (SPE) was fabricated for the electrochemical detection of phenothiazine (PTZ). The electrocatalytic oxidation behavior of PTZ on a modified electrode was tested using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Interestingly, the fabricated f-CNF/Er₂MoO₆-modified SPE was characterized to have a broad dynamic linear range from 0.025 to 80 µM, a limit of detection (LOD) of 0.008 µM, and a sensitivity of 3.707 μA μM⁻¹ cm⁻² towards the electrochemical oxidation of PTZ. Moreover, the PTZ sensor exhibited good stability, selectivity, and well precision. The practicality of the PTZ sensor was tested in human urine samples.