Phase-controlled synthesis of monodispersed porous In2O3 nanospheres via an organic acid-assisted hydrothermal process

Phase-pure porous nanospheres, both In(OH)(3) and InOOH, have been prepared through a facile hydrothermal method using different organic acids as the assistant agents. The organic acids play an important role in the phase change, and the phase composition of the precursors could be deliberately controlled by adjusting the organic acid (citric acid or tartaric acid). Cubic and hexagonal In2O3 monodispersed nanospheres with porosity can be obtained from In(OH)(3) and InOOH, respectively, while size and morphology can be maintained to a certain extent. The as-synthesized porous In2O3 nanospheres are composed of numerous small nanocrystallites and possess good size uniformity. Influencing factors such as the reaction time and the type and amount of organic acids were systematically investigated. A possible ethylenediamine or tartaric acid coordinated mechanism of the phase-control synthesis of In2O3 was proposed based on the experimental results. Furthermore, the potentialities of the porous In2O3 nanospheres were also studied by room-temperature photoluminescence (PL) spectroscopy.