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Electrocatalytic water-splitting catalysts play important roles in clean energy conversion systems. Herein, metal–organic framework-derived (MOF-derived) hollow CoS x @MoS2 microcubes were successfully synthesized by a novel method. Co-MOF [(CH3)2NH2]­[Co­(HCOO)3] prepared by a simple liquid precipitation method at room temperature reacted with S2– released from thioacetamide (TAA) to generate Co9S8 under solvothermal conditions. Through hydrothermal treatment, numerous MoS2 nanosheets grew on the surface of CoS x vertically and uniformly after introduction of sulfur and molybdenum sources, finally generating CoS x @MoS2 heterostructures. As bifunctional electrocatalysts, the heterostructures exhibited remarkable performance for the hydrogen evolution reaction with a low overpotential of 239 mV when the current density increased up to 10 mA cm–2 and a small Tafel slope of 103 mV dec–1 in 0.5 M H2SO4. They also worked effectively for the oxygen evolution reaction with a low overpotential of 347 mV at 10 mA cm–2 in 1 M KOH. The enhanced electrocatalytic activities of CoS x @MoS2 can be ascribed to their unique heterostructures and the synergism between CoS x and MoS2.

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Metal-organic framework-based supercapacitors have been widely recognized as the best energy storage devices for future portable electronic equipment. Herein, CoP- T ( T = 300, 350, and 400 °C) microcubes with a solid and hollow microstructure were successfully synthesized by low-temperature phosphorization of [CHNH][Co(HCOO)] precursor at desired temperatures. The morphology, structure, and composition of the prepared CoP-350 °C samples were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Hollow CoP-350 °C microcube has a larger specific surface area (25.9 m g) than that of solid ones (16.1 m g). When the two samples were used as electrode raw materials for supercapacitors, the hollow CoP-350 °C electrode exhibits better electrochemical performance (560 F g) than that of the solid one (427.6 F g) at a current density of 1 A g. The enhanced supercapacitor properties may be attributed to the large surface area and the unique hollow structure. Further, an asymmetric supercapacitor was prepared by employing the hollow CoP-350 °C microcubes as anode and N-doped graphene as cathode. It has a high rate capability (capacitance retention of 69% from 0.5 to 8 A g), a high energy density (21.4 W h kg at a power density of 373 W kg), and outstanding cycling stability (remained 81.2% after 6000 cycles).

The visible-blind ultraviolet (UV) photodetector can detect UV signals and is not interfered by visible light or infrared light in the environment. In order to realize high-performance visible-blind UV organic...