Enhanced Photocatalytic Properties of Mesoporous SnO₂ Induced by Low Concentration ZnO Doping

Mesoporous SnO₂ doped with a low concentration of ZnO (m-SnO₂/ZnO), prepared through a hydrothermal method by using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent, has been characterized by transmission electron microscopy, powder X-ray diffraction, and nitrogen adsorption−desorption technologies. It was found that doped m-SnO₂ showed different properties compared with undoped mesoporous SnO₂ (m-SnO₂). The former not only had a larger Brunauer−Emmett−Teller (BET) surface area but also showed a more stable mesoporous structure against high-temperature sintering than did the latter. Furthermore, m-SnO₂/ZnO exhibited a significant enhancement of photocurrent and photocatalytic capability toward degrading rhodamine B (RhB) compared to undoped mesoporous SnO₂. The improvement of photocatalytic activity for m-SnO₂/ZnO might be attributed to its higher specific surface area and enhanced charge separation that derive from the coupling of ZnO with SnO₂.