“…Up to now, different novel morphologies of SnO 2 , such as nanoparticles, nanorods, nanotubes, nanodiskettes, nanoboxes, hollow spheres, and mesoporous structures [14][15][16][17][18][19][20][21], have been designed. As known, the hierarchical porous material has been studied extensively for its wide applications such as HPLC separation, bone-tissue implants, catalysis, electrode materials for fuel cell application, heterogeneous colorimetric sensors, biomaterials engineering and controlled drug delivery devices, photovoltaic cells and energy conversion applications [22][23][24][25][26][27][28][29]. To the best of our knowledge, the production of hierarchical porous SnO 2 has never been reported before.…”