Enhanced cathodic electrogenerated chemiluminescence of luminol at a MXene–Nafion composite-modified electrode in neutral aqueous solution

Electrogenerated chemiluminescence (ECL) of luminol was studied on a two-dimensional titanium carbide (MXene)–Nafion composite-modified glassy carbon (GC) electrode in a neutral aqueous solution (pH 7). In the present work, Ti₃C₂T_x MXene was dispersed in a cation-exchange ionomer (Nation) and the resulting MXene–Nafion composite solution was drop-cast on the surface of GC electrode. Due to the strong electrocatalytic activity of the MXene towards the reduction reactions of oxygen and hydrogen peroxide, strong cathodic ECL emissions of luminol related to those reactions were obtained in a neutral aqueous solution. Based on the significant enhancement effect of hydrogen peroxide on the cathodic ECL, the present ECL sensor can detect hydrogen peroxide in the concentration range of 1.0 × 10⁻⁸ M ∼ 1.0 × 10⁻³ M with a detection limit of 3.1 × 10⁻⁹ M (S/N = 3). Furthermore, the present ECL sensor exhibits good selectivity towards hydrogen peroxide against interfering species such as glucose, ascorbic acid and uric acid. Therefore, the present ECL sensor could offer a good opportunity to be employed as an alternative transducer for the oxidase-based biosensors in biological fluids.