Polyoxometalate [PMo11O39]7−/carbon nanocomposites for sensitive amperometric detection of nitrite

The polyoxometalate [PMo11O39]7− was synthesized and used as catalyst for the reduction of nitrite ions. This mono-lacunary keggin anion, cited as PMo11, was confined within a matrix of either oxidized single-walled carbon nanotubes (ox-SWCNTs) or reduced graphene oxide (rGO) on glassy carbon (GC) electrodes to improve the electron transfers. Five different configurations were characterized using cyclic voltammetry and evaluated in an amperometric sensor setup for nitrite detection where the amount of the different components were optimized. The configuration using only ox-SWCNTs and PMo11 on GCE showed best sensitivities of up to 44.41 mA Lmol−1 and a satisfying reproducibility (RSD: ∼2.64% for four identic electrodes). Furthermore, a linear range between 3.0 × 10−5 mol L−1 and 1.6 × 10−2 mol L−1 with a detection limit of 3.0 × 10−5 mol L−1 was obtained. The final sensor setup also showed good selectivity towards interfering ions.

The polyoxometalate [PMo11O39]7− confined in nanostructured carbon matrices was evaluated as catalyst for the selective electrochemical detection of nitrite ions.146