One-pot hydrothermal synthesis of uniform β-MnO2 nanorods for nitrite sensing.

A simple hydrothermal method was developed for the synthesis of uniform single-crystal β-MnO(2) nanorods only using potassium permanganate and sodium nitrite in acidic solution, without any seed or template. The as-prepared β-MnO(2) nanorods have the average diameter of 300±20 nm and a length up to 1.2±0.2 μm. Moreover, the effects of pH, temperature, and reactant molar ratios on the morphology of the final product were studied in detail. In addition, the catalytic ability of the as-prepared β-MnO(2) nanorods was tested for the electrooxidation of nitrite. The resulting sensor showed a wide linear range from 0.29 μM to 26.09 mM (R=0.9986), high sensitivity (1.21 μA mM(-1), S/N=3), low detection limit (0.29 μM), and fast response (less than 5 s).