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Highlights: The large-scale, high-strength, super-tough, and multifunctional nacre-like heterocyclic aramid (HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite papers were fabricated using the in-situ assembly of PPy onto the HA/MXene hydrogel template. The "brick-and-mortar" layered structure and abundant hydrogen-bonding interactions among MXene, PPy, and HA respond cooperatively to external stress and effectively increase the mechanical properties of HMP nanocomposite papers. The templating effect from HA/MXene was utilized to guide the assembly of conducting polymers, leading to high electrical conductivity and outstanding electromagnetic interference shielding performance. Robust, ultra-flexible, and multifunctional MXene-based electromagnetic interference (EMI) shielding nanocomposite films exhibit enormous potential for applications in artificial intelligence, wireless telecommunication, and portable/wearable electronic equipment. In this work, a nacre-inspired multifunctional heterocyclic aramid (HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper with large-scale, high strength, super toughness, and excellent tolerance to complex conditions is fabricated through the strategy of HA/MXene hydrogel template-assisted in-situ assembly of PPy. Benefiting from the "brick-and-mortar" layered structure and the strong hydrogen-bonding interactions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa), outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect of HA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly, the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dB at an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2 g−1. In addition, the papers also have excellent applications in electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developing high-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management. [ABSTRACT FROM AUTHOR]

MXenes, a burgeoning family of 2D materials with high conductivity and large specific surface area, are ideal electromagnetic absorbing materials. However, the ample polar functional groups lead to poor dispersion in the non‐polar matrix, limiting its application in non‐polar‐polymer‐based composites. With the help of the shear rheological properties of SiO2, the conflict is resolved here by directly dispersing MXene aqueous dispersion into the non‐polar resin. Water is locked dynamically through SiO2 nanoparticles among the MXene@SiO2 nanosheets, suppressing MXene's self‐restacking and aggregation in the resin matrix. Therefore, the fabrication of uniform MXene/non‐polar polymer composites is achieved. Meanwhile, this method allows different nanoparticles (Fe3O4, etc.) to be evenly dispersed among the MXene nanosheets to further improve the composites' electromagnetic parameters. The as‐prepared composites achieve remarkable absorbing performance with a low MXene concentration (≤5 wt.‰). The SMEP‐h achieves the maximum reflection loss value of over 60 dB at 12 GHz (at the thickness of 2.15 mm), and the SMEP‐F possesses a broad effective absorbing bandwidth of over 6.18 GHz (at the thickness of 1.75 mm). The shear‐rheological‐assisted MXene dispersion method in the non‐polar matrix paves an avenue for the design of outstanding MXene‐based electromagnetic absorbing composites. [ABSTRACT FROM AUTHOR]

• Pristine and bilayers of group-III-V compounds and hydrogenated ones are studied. • The full hydrogenation induces an indirect-to-direct bandgap transition. • Tunable band gaps of group-III-V compounds with the biaxial strain. • The electron-hole pairs are effectively separated in four vdW heterostructures. • The optical spectra of GaP/GaPH2 and GaAs/GaAsH2 are enhanced in VIS light region. Density functional theory calculations were performed to investigate the structural, electronic, and optical properties of two-dimensional hexagonal III-V binary compounds (h-MX, M = B, Al, Ga, and X = N, P and As), the fully hydrogenated counterparts (MXH 2) and the MX/MXH 2 van der Waals (vdW) heterostructures. The results show that hydrogenation can change the stability and electronic band dispersion of hexagonal III-V binary compounds, of which the fully hydrogenated h-AlN becomes dynamically unstable. The full hydrogenation induces an indirect-to-direct bandgap transition for hexagonal BN, GaN, GaP, GaAs, and the band gaps become tunable by applying the biaxial strain.These characteristics are conducive to design of strain-based 2D materials for application in nanoelectronic and optoelectronic devices. Furthermore, the different stacking pattern MX/MXH 2 vdW heterostructures have been investigated. Of which, BN/BNH 2 , GaN/GaNH 2 , GaP/GaPH 2 and GaAs/GaAsH 2 were found to have the typical type-II band alignments, which can facilitate the effective separation of photogenerated electrons and holes. The calculated band alignment and enhanced optical absorption suggest that the GaP/GaPH 2 and GaAs/GaAsH 2 vdW heterostructures possess great potential to be high-performance optoelectronic device. [ABSTRACT FROM AUTHOR]