Porous and hollow nanomaterials have been an exciting research area for numerous next-generation technological applications. However, it is still a challenge to assemble porous and hollow nanostructures of appropriate composition and characteristics in designed architectures. Here, we report a self-templated metal− organic frameworks based strategy for the synthesis and engineering of porous and hollow nanostructures in designed architectures by developing graphitic-carbonintermingled porous Co 3 O 4 nanotentacles, for the first time, on electrospun hollow carbon nanofibers in a designed 3D pattern (3D Co 3 O 4 /C@HCNFs). The asdeveloped nanocomposite sheet, as a free-standing electrode for supercapacitors, shows a high specific capacity of 199 mA h g −1 (1623 F g −1 ) at 1 A g −1 with good cyclic life and outstanding rate capability. Moreover, the assembled asymmetric supercapacitor device supplies an energy density of 36.6 W h kg −1 at the power density of 471 W kg −1 with significant cyclic life and rate capability indicating its potential practical application. This synthetic strategy suggests a simple, cost-effective and convenient route for the synthesis and assembly of porous and hollow structured nanomaterials in designed architectures for diverse applications.

The scrupulous designation of hollow and porous electroactive materials incorporating prolific redox-active polyphase transition-metal oxide decorated with polyphase transitionmetal sulfide onto rGO (reduced graphene oxide)-supported conductive substrate has never been an easy task due to the very good coordination affair of sulfur toward transition metals. Herein, cost-effective hydrothermal growth followed by a metal−organic framework (MOF)-mediated sulfidation approach is employed to achieve burl-like Ni−Co−S nanomaterial-integrated hollow and porous NiMoO 4 nanotubes onto rGO-coated Ni foam (rGO− NiMoO 4 @Ni−Co−S) as the electrode material for supercapacitors. The open framework of the rGO−Co−MOF template after the etching and sulfidation process not only enables the creation of a tubular structure of NiMoO 4 nanorods but also provides convenient ion−electron pathways to promote rapid faradic reactions for the hybrid composite electrode. Owing to the unique hollow and tubular structure, the as-fabricated rGO−NiMoO 4 @ Ni−Co−S electrode exhibits a high specific capacity of 318 mA h g −1 at 1 A g −1 and remarkable cyclic performance of 88.87% after 10,000 consecutive charge−discharge cycles in an aqueous 2 M KOH electrolyte on a three-electrode configuration. Moreover, the assembled rGO−NiMoO 4 @Ni−Co−S//rGO−MDC (MOF-derived carbon) asymmetric supercapacitor device exhibits a satisfactory energy density of 57.24 W h kg −1 at a power density of 801.8 W kg −1 with an admirable life span of 90.89% after 10,000 repeated cycles.

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