MnO2 nanoarrays: an efficient catalyst electrode for nitrite electroreduction toward sensing and NH3 synthesis applications.

It is highly attractive to develop efficient electrocatalysts for the sensitive and selective detection of nitrite. In this communication, we report that an MnO2 nanoarray on titanium mesh (MnO2 NA/TM) is an efficient catalyst electrode for the electroreduction of nitrite. Electrochemical measurements demonstrate that the constructed MnO2 NA/TM sensor offers a superior sensing performance, having a short response time of 3 s, a wide detection range of 1.0 μM to 5.0 mM, a low detection limit of 1.5 nM (S/N = 3), and a response sensitivity of 10 301 μA mM-1 cm-2, with satisfactory selectivity, specificity, and reproducibility. This electrochemical system is also capable of catalyzing the electrochemical reduction of nitrite to NH3 with a transformation efficiency of 6%.