A silk nanofiber‐networked bio‐triboelectric generator (Silk Bio‐TEG) is developed using an eco‐friendly and sustainable silk biomaterial with strong hydrogen bonding between peptide blocks. The electrospun Silk Bio‐TEG shows highly durable and reliable energy harvesting performances due to its notably high surface‐to‐volume ratio, mechanically super‐strong silk fibers, and fracture tolerant behavior of nanofiber‐networks.

MXenes, a member of 2D inorganic compounds that contain few-atom-thick layers of transition metal carbides, nitrides, and polar surface functional groups, are extraordinary materials for many applications including stimuliresponsive actuators. Here, an extensive review on MXene-based actuators in comparison with other 2D materials-based actuators is reported, highlighting the main differences in view of chemical structure, mechanical properties, and electrical functionalities. First, since MXenes are newcomers in the field of actuators, their properties are explained including cation and ionic liquid intercalation, high capacitance, good electrical and thermal conductivity, excellent electromagnetic wave absorption, hydrophilicity, and outstanding dispersion in many polar solvents. Second, electro-ionic, electrochemical, electrothermal, photothermal, and humidity-responsive MXene-based actuators are comprehensively addressed with detailed actuation mechanisms, focusing on electro-ionic soft actuators. Third, several applications of those actuators are summarized with an emphasis on soft robotics and future directions of MXene-based actuators are suggested.

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Atomic-scale defects on carbon nanostructures have been considered as detrimental factors and critical problems to be eliminated in order to fully utilize their intrinsic material properties such as ultrahigh mechanical stiffness and electrical conductivity. However, defects that can be intentionally controlled through chemical and physical treatments are reasonably expected to bring benefits in various practical engineering applications such as desalination thin membranes, photochemical catalysts, and energy storage materials. Herein, we report a defect-engineered self-assembly procedure to produce a three-dimensionally nanohole-structured and palladium-embedded porous graphene hetero-nanostructure having ultrahigh hydrogen storage and CO oxidation multifunctionalities. Under multistep microwave reactions, agglomerated palladium nanoparticles having diameters of ∼10 nm produce physical nanoholes in the basal-plane structure of graphene sheets, while much smaller palladium nanoparticles are readily impregnated inside graphene layers and bonded on graphene surfaces. The present results show that the defect-engineered hetero-nanostructure has a ∼5.4 wt % hydrogen storage capacity under 7.5 MPa and CO oxidation catalytic activity at 190 °C. The defect-laden graphene can be highly functionalized for multipurpose applications such as molecule absorption, electrochemical energy storage, and catalytic activity, resulting in a pathway to nanoengineering based on underlying atomic scale and physical defects.

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