From the in situ reduction of permanganate on the surface of AC, MnOx was accumulated and it formed films on the outer surface of the AC. Table 1 shows the thickness and actual loadings of MnOx/AC for the different nominal Mn loadings. With the increase of nominal manganese loading, the actual loading also increased. Figure 1 shows the surface and cross-sectional morphologies of MnOx with different nominal Mn loadings. When the nominal Mn loading was 0.44%, a porous lichen-like structure with a thickness of 180–190 nm, which was assembled from curled MnOx nanobelts, was observed by SEM. When the Mn loading was increased to 1.1%, the lichen-like structure remained, but the MnOx layer became denser and the thickness was increased to 330–365 nm. On the 5.5% MnOx/AC sample, the loose lichen-like morphology had largely collapsed, and compact nanospheres were present on the surface with thickness of 290–350 nm. For the 11% MnOx/AC, the lichen-like structure had completely disappeared, and on this catalyst, the MnOx nanobelts were stacked into nanospheres with the thickness of the MnOx layer increasing to 590–710 nm.