Bioactive ceramics have received great attention in the past decades owing to their success in stimulating cell proliferation, differentiation and bone tissue regeneration. They can react and form chemical bonds with cells and tissues in human body. This paper provides a comprehensive review of the application of bioactive ceramics for bone repair and regeneration. The review systematically summarizes the types and characters of bioactive ceramics, the fabrication methods for nanostructure and hierarchically porous structure, typical toughness methods for ceramic scaffold and corresponding mechanisms such as fiber toughness, whisker toughness and particle toughness. Moreover, greater insights into the mechanisms of interaction between ceramics and cells are provided, as well as the development of ceramic-based composite materials. The development and challenges of bioactive ceramics are also discussed from the perspective of bone repair and regeneration.
For increasing scalability and reducing cost, transition metal dichalcogenides‐based electrocatalysts presently have been proposed as substitutes for noble metals to generate hydrogen, but these alternatives usually suffer from inferior performance. Here, a Ravenala leaf‐like WxC@WS2 heterostructure is grown via carbonizing WS2 nanotubes, whose outer walls being partially unzipped along with the Wx C “leaf‐valves” attached to the inner tubes during the carbonization process. This heterostructure exhibits a catalytic activity for hydrogen evolution reaction with low overpotential of 146 mV at 10 mA cm−2 and Tafel slope of 61 mV per decade, outperforming the performance of WS2 nanotubes and WxC counterparts under the same condition. Density functional theory calculations are performed to unravel the underlying mechanism, revealing that the charge distribution between WxC and WS2 plays a key role for promoting H atom adsorption and desorption kinetics simultaneously. This work not only provides a potential low‐cost alternative for hydrogen generation but should be taken as a guide to optimize the catalyst structure and composition.
Transfer of large‐scale 2D atomic layers onto desired targets is crucial for the integration toward practical applications. Conventional wet etching transfer of 2D materials grown on insulating substrates suffers from the degraded film quality caused by the prolonged exposure of harsh chemicals. Also, both the detaching from initial substrate and the attaching to target processes are not spatially deterministic. Herein, by adopting the water‐soluble polyvinyl alcohol as a viscoelastic mediator and polymethyl‐methacrylate as a protecting layer, a green and robust transfer technique is developed for various grown 2D materials. This method is of high degree of freedom, which can realize both selective peel‐off and aligned release. The transferred materials maintain their pristine qualities, as probed by various spectroscopic/microscopic characterizations. This technique promises a universal applicability for a diverse range of 2D materials and growth/target substrates, facilitating facile fabrication of 2D electronic devices with improved performance. Furthermore, by performing restacking steps, van der Waals heterostructures can be built. As a proof of concept, the artificial assembly of monolayer MoS2/WSe2 heterostructure is fabricated, and the strong interlayer coupling from photoluminescence quenching and emerging Raman modes at the junction areas is found, indicating that the method guarantees the ideal interfaces between the transferred materials.
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