Herein, we present a facile metal–organic framework-engaged strategy to synthesize hollow Co3S4@MoS2 heterostructures as efficient bifunctional catalysts for both H2 and O2 generation. The well-known cobalt-based metal–organic zeolitic imidazolate frameworks (ZIF-67) are used not only as the morphological template but also as the cobalt precursor. During the two-step temperature-raising hydrothermal process, ZIF-67 polyhedrons are first transformed to hollow cobalt sulfide polyhedrons by sulfidation, and then molybdenum disulfide nanosheets further grow and deposit on the surface of hollow cobalt sulfide polyhedrons at the increased temperature. The crystalline hollow Co3S4@MoS2 heterostructures are finally obtained after subsequent thermal annealing under a N2 atmosphere. Due to the synergistic effects between the hydrogen evolution reaction active catalyst of MoS2 and the oxygen evolution reaction active catalyst of Co3S4, the obtained hollow Co3S4@MoS2 heterostructures exhibit outstanding bifunctional catalytic performances toward both hydrogen and oxygen evolution reactions in acidic and alkaline media.

Metal-organic frameworks (MOFs) with high porosity and a regular porous structure have emerged as a promising electrode material for supercapacitors, but their poor electrical conductivity limits their utilization efficiency and capacitive performance. To increase the overall electrical conductivity as well as the efficiency of MOF particles, three-dimensional networked MOFs are developed via using preprepared conductive polypyrrole (PPy) tubes as the support for in situ growth of MOF particles. As a result, the highly conductive PPy tubes that run through the MOF particles not only increase the electron transfer between MOF particles and maintain the high effective porosity of the MOFs but also endow the MOFs with flexibility. Promoted by such elaborately designed MOF-PPy networks, the specific capacitance of MOF particles has been increased from 99.2 F g for pristine zeolitic imidazolate framework (ZIF)-67 to 597.6 F g for ZIF-PPy networks, indicating the importance of the design of the ZIF-PPy continuous microstructure. Furthermore, a flexible supercapacitor device based on ZIF-PPy networks shows an outstanding areal capacitance of 225.8 mF cm, which is far above other MOFs-based supercapacitors reported up to date, confirming the significance of in situ synthetic chemistry as well as the importance of hybrid materials on the nanoscale.

A simple method is developed to prepare Mo2C-embedded mesoporous N-doped carbon nanosheets which assemble into hollow spheres.

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Although multilayer films have been extensively reported, most compositions have been limited to non-catalytically active materials (e.g. polymers, proteins, lipids, or nucleic acids). Herein, we report the preparation of binder-free multilayer metallic mesoporous films with sufficient accessibility for high electrocatalytic activity by using a programmed electrochemical strategy. By precisely tuning the deposition potential and duration, multilayer mesoporous architectures consisting of alternating mesoporous Pd layers and mesoporous PdPt layers with controlled layer thicknesses can be synthesized within a single electrolyte, containing polymeric micelles as soft templates. This novel architecture, combining the advantages of bimetallic alloys, multilayer architectures, and mesoporous structures, exhibits high electrocatalytic activity for both the methanol oxidation reaction (MOR) and the ethanol oxidation reaction (EOR).

Cobalt sulfide/sulfur dopedc arbon composites (Co 9 S 8 /S-C) were synthesized by calcining ar ationally designed sulfur-containing cobalt coordinationc omplexi na n inert atmosphere.F rom the detailed transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analyses,t he electrocatalytically active Co 9 S 8 nanoparticles were clearly obtained and combined with the thin sulfur doped carbon layers. Electrochemical data showed that Co 9 S 8 /S-C had ag ood activity and long-term stability in catalyzing oxygen evolution reactioni na lkaline electrolyte, even better than the traditional RuO 2 electrocatalyst. The excellente lectrocatalytic activity of Co 9 S 8 /S-C was mainly attributed to the synergistic effect between the Co 9 S 8 catalyst which contributed to the oxygen evolutionr eactiona nd the sulfurd oped carbon layer whichf acilitated the adsorption of reactants, prevented the Co 9 S 8 particles from aggregating and served as the electrically conductivebinder between each component.

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