Abstract:
MnO
2 nanorod and sea urchin microspheres were prepared using the hydrothermal method, and Mn-Ag composite oxides were prepared by in-situ doping with 5% Ag. The as-prepared samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), BET, Raman and other characterization techniques, and the removal performance of different catalysts for toluene was investigated. It was found that the amount of (NH
4)
2S
2O
8 would affect MnO
2 morphology. MnO
2 nanorods were formed when (NH
4)
2S
2O
8 was 2.28 g, while MnO
2 sea urchin microspheres were formed when (NH
4)
2S
2O
8 was 6.84 g. There was no morphology change of MnO
2 nanorods after 5% Ag doping. However, the nanowires on the surface of MnO
2 sea urchin microspheres increased when 5% Ag was doped, and the entanglement phenomenon occurred, forming a hollow bird's nest structure. After 5% Ag doping, there was no effect on the crystal of MnO
2 nanorods and sea urchin microspheres, both of which were
α-MnO
2, but a diffraction peak of Mn
2O
3 appeared in 5% Ag-MnO
2 nanorods. Compared to MnO
2 nanorods, MnO
2 sea urchin microspheres showed an increasing trend of specific surface area, pore size and pore volume. The doping of Ag further increased the specific surface area, pore size and pore volume of MnO
2 sea urchin microspheres. For the toluene removal, MnO
2 sea urchin microspheres showed a better toluene removal performance than MnO
2 nanorods, and 5% Ag-MnO
2 sea urchin microspheres showed the best toluene removal performance among all the catalysts.