Promoting effects of Ag on In2O3 nanospheres of sub-ppb NO2 detection

Herein, high performance of sub-ppb NO2 sensors were fabricated based on Ag nanoparticles (NPs) decorated on hierarchical In2O3 nanospheres assembled by several nanocubes subunit via a facile hydrothermal route and the subsequent decoration process. The morphology evolution of the nanospheres is investigated, which revealed that the nanocubes of the nanospheres shared the same surface and self-assembled together according to the oriented attachment mechanism. When performing as sensors, such nanostructures possessed relatively good sensitivity to NO2. With respect to the decoration of Ag NPs, the sensing performances can be further remarkably promoted on account of the catalyst activation and spill-over effect.