Figure 1

High-resolution TEM images and electron diffraction patterns of (a) ZrO2 (b) ZrO2-B, and (c) Cr@ZrO2 NPs. (d) XRD patterns and (e) Raman spectra of ZrO2, ZrO2-B, and Cr@ZrO2 NPs. The inset of (e) shows the Raman shift of ZrO2-B NPs toward the lower energy region. # and * indicate the Ag and Bg Raman vibrational modes, respectively.