Large-area synthesis of high-quality β-MnO2 nanowires and the mechanism of formation through a facile mineralization process

High-quality large-area β-MnO2 nanowires can be easily synthesized using KNO3 as the mineralizing agent in a process of mineralization from Mn(NO3)2 aqueous solution. The morphological evolution of the β-MnO2 nanowires and the influences of mineralizing agents and their concentrations on the morphology of the final products were investigated in detail. KNO3 was the best mineralizing agent among KNO3, NaNO3, KCl, and NaCl. More interestingly, when the concentration of the mineralizing agent KNO3 was not saturated, only irregular short faceted nanorods, instead of nanowires, can be observed. Finally, the formation mechanism is discussed.