“…2A, the XRD pattern of MnO 2 @Co 3 O 4 shows strong diffraction peaks at 22.1°, 36.84°, 43.08°, 52.56°, 70.22°, and 77.52°, corresponding to the (111), (220), (311), (400), (511) and (440) facets of Co 3 O, respectively. 19 The crystal size of the Co 3 O 4 NPs calculated using the spinel (111) plane (at 2 θ = 21.98°) was 7.44 nm according to the Debye–Scherrer equation. It was found that the obtained Co 3 O 4 have abundant exposed high-energy (111) facets, which have been demonstrated to be more active than (001) crystal facets in catalysis and sensing.…”