Fig. 1: Characterizations of as-prepared BaTiO₃ NPs.

a XRD spectra. b Enlarged (002) and (200) XRD peaks. c UV-Vis diffuse reflectance spectra with Tauc’s plot as inset. d UPS. e SEM image. f HRTEM image. The inset in (f) is the SAED pattern along [011] zone axis. Source data are provided as a Source Data file.