Hybridizing nanostructured metal oxides with multiwalled carbon nanotubes (MWCNTs) is highly desirable for the improvement of electrochemical performance of lithium-ion batteries. Here, a facile and scalable strategy to fabricate hierarchical porous MWCNTs/Co3O4 nanocomposites has been reported, with the help of a morphology-maintained annealing treatment of carbon nanotubes inserted metal organic frameworks (MOFs). The designed MWCNTs/Co3O4 integrates the high theoretical capacity of Co3O4 and excellent conductivity as well as strong mechanical/chemical stability of MWCNTs. When tested as anode materials for lithium-ion batteries, the nanocomposite displays a high reversible capacity of 813 mAh g(-1) at a current density of 100 mA g(-1) after 100 charge-discharge cycles. Even at 1000 mA g(-1), a stable capacity as high as 514 mAh g(-1) could be maintained. The improved reversible capacity, excellent cycling stability, and good rate capability of MWCNTs/Co3O4 can be attributed to the hierarchical porous structure and the synergistic effect between Co3O4 and MWCNTs. Furthermore, owing to this versatile strategy, binary metal oxides MWCNTs/ZnCo2O4 could also be synthesized as promising anode materials for advanced lithium-ion batteries.

Highly uniform hierarchical Mo-polydopamine hollow spheres are synthesized for the first time through a liquid-phase reaction under ambient temperature. A self-assembly mechanism of the hollow structure of Mo-polydopamine precursor is discussed in detail, and a determined theory is proposed in a water-in-oil system. Via different annealing process, these precursors can be converted into hierarchical hollow MoO /C and Mo C/C composites without any distortion in shape. Owing to the well-organized structure and nanosize particle embedding, the as-prepared hollow spheres exhibit appealing performance both as the anode material for lithium-ion batteries and as the catalyst for hydrogen evolution reaction (HER). Accordingly, MoO /C delivers a high reversible capacity of 940 mAh g at 0.1 A g and 775 mAh g at 1 A g with good rate capability and long cycle performance. Moreover, Mo C/C also exhibits an enhanced electrocatalytic performance with a low overpotential for HER in both acidic and alkaline conditions, as well as remarkable stability.

The core–shell MOF templated synthesis of porous NiFe2O4@Fe2O3 nanotubes that exhibit a large reversible capacity, excellent cycling stability and superior rate capability as anode materials for Li-ion batteries.

Hierarchical porous core-shell NiFe2O4@TiO2 nanorods have been fabricated with the help of hydrothermal synthesis, chemical bath deposition, and a subsequent calcinating process. The nanorods with an average diameter of 48 nm and length of about 300-600 nm turn out have a highly uniform morphology and are composed of nanosized primary particles. Owing to the synergistic effect of individual constituents as well as the hierarchical porous structure, the novel core-shell NiFe2O4@TiO2 nanorods exhibit superior electrochemical performance when evaluated as anode materials for lithium-ion batteries. At the current density of 100 mA g(-1), the composite exhibits a reversible specific capacity of 1034 mAh g(-1) up to 100 charge-discharge cycles, which is much higher than the uncoated NiFe2O4 nanorods. Even when cycled at 2000 mA g(-1), the discharge capacity could still be maintained at 358 mAh g(-1).

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Novel 3D hierarchical flower-like Co 1−x S architectures were successfully synthesized via a hydrothermal process using trisodium citrate (Na 3 Cit) as a chelating agent. The crystal structure and morphology of the as-prepared products were characterized and the results demonstrated that the Na 3 Cit could efficiently control the formation of flower-like Co 1−x S hierarchitectures. A possible growth mechanism for this hierarchical flower-like Co 1−x S nanostructure was proposed on the basis of a series of time-dependent experiments, and this work provides an efficient route for designing desirable micro-/nanostructures.The flower-like Co 1−x S nanostructures were fabricated as anode materials of lithium ion batteries and tested in the range of 0.01 V-3.00 V. The initial discharge capacity was up to 1244 mAh g −1 at the current density of 50 mA g −1 . The electrochemical measurement suggested that the flower-like Co 1−x S nanostructures have high capacity and excellent cycle stability as a Li-ion battery anode.

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Green H2 production from renewable energy sources by water splitting is desired to reduce the use of fossil fuels and CO2 emissions. The past decade has witnessed the fast development of electrolytic water splitting for H2 generation, with most of the studies focusing on the development of superior electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Equally important is the innovation of water splitting system design to tackle the critical issues confronted by conventional water electrolysis. Some interesting developments have recently emerged with additional redox-mediated process to separate the HER and OER in time and space. In this Review, the various strategies for decoupled H2 production are critically reviewed. Based on the additional process, which is introduced in conjunction with the electrochemical process for decoupled electrochemical or chemical H2 production, the distinct operating principle is highlighted for each strategy, and the underlying connections to other strategies are delineated. Lastly, the implications of the decoupled operations in addressing the formidable issues of conventional water electrolysis, their inherent constraints for practical implementation, and potential solutions are broadly discussed.