Fig. 2From: Hollow Ni/NiO/C composite derived from metal-organic frameworks as a high-efficiency electrocatalyst for the hydrogen evolution reactionSEM images of a H–Ni/NiO/C and b NH–Ni/NiO/C, c TEM, d HR-TEM, e Scanning TEM images of H–Ni/NiO/C with corresponding element maps of f Ni, g O, and h CBack to article page