A sensitive amperometric bromate sensor based on multi-walled carbon nanotubes/phosphomolybdic acid composite film

An amperometric sensor for bromate was developed based on multi-walled carbon nanotubes (MWNTs)/phosphomolybdic acid (PMo₁₂) composite film coated on a pyrolytic graphite (PG) electrode. MWNTs are dispersed in PMo₁₂ aqueous solution through spontaneous and strong chemisorption between carbon and polyoxometalate, which results in a homogeneous MWNTs/PMo₁₂ composite. Due to the unique electronic and electrocatalytic properties of MWNTs and PMo₁₂, the combination of MWNTs and PMo₁₂ results in a remarkable synergistic augmentation on the response current. The bromate sensor based on the PG/MWNTs/PMo₁₂ electrode has excellent characteristics, such as a detection limit of 0.5 μM, a sensitivity of 760.9 μA mM⁻¹ cm⁻², a response time less than 2 s and a linear range from 5 μM to 15 mM.