The development of cost-effective electrocatalysts for both hydrogen and oxygen evolution reactions (HER and OER) in alkaline media is crucial in renewable energy conversion technologies. Metal–organic frameworks (MOFs) can act as precursors to the design and construct of varied nanostructured materials which may be difficult to produce in other ways. Herein, we put forward a serial ion-exchange reaction and selenation strategy to prepare novel yolk–shelled Ni–Co–Se dodecahedral nanocages on carbon fiber paper (Y–S Ni–Co-Se/CFP). ZIF-67@LDH/CFP was first synthesized by a simple ion-exchange reaction, followed by a hydrothermal selenation process to form Y–S Ni–Co-Se/CFP. Moreover, the composition of the as-prepared yolk–shelled Ni–Co–Se nanocages was a mixture of Co0.85Se and Ni0.85Se (Co/Ni atomic ratio of about 2.42). Due to their structural and compositional merits, the as-prepared Y–S Ni–Co-Se/CFP exhibited remarkable electrocatalytic activity and long-term stability (over 80% current retention for at least 18 h) for both HER and OER. For HER, it required an overpotential of 250 mV to attain a current density of 10 mA cm–2, which was 162 mV less than that of the Y–S Co0.85Se/CFP counterpart. The catalyst also efficiently catalyzed OER with a current density of 10 mA cm–2 at an overpotential of 300 mV, which was lower than those of other reported Co-based catalysts.

Polyimide aerogels with mechanical robustness, great compressibility, excellent antifatigue properties, and intriguing functionality have captured enormous attention in diverse applications. Here, enlightened by the xylem parenchyma of dicotyledonous stems, a radially architectured polyimide/MXene composite aerogel (RPIMX) with reversible compressibility is developed by combining the interfacial enhancing strategy and radial ice-templating method. The strong interaction between MXene flakes and polymer can glue the MXene to form continuous lamellae, the ice crystals grow preferentially along the radial temperature gradient can effectively constrain the lamellae to create a biomimetic radial lamellar architecture. As a result, the nature-inspired RPIMX composite aerogel with centrosymmetric lamellar structure and oriented channels manifests excellent mechanical strength, electrical conductivity, and water transporting capability along the longitudinal direction, endowing itself with intriguing applications for accurate human motion monitoring and efficient photothermal evaporation. These exciting properties make the biomimetic RPIMX aerogels promising candidates for flexible piezoresistive sensors and photothermal evaporators.

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Conductive elastomer composites are widely recognized as prospective strain sensing materials in soft robotics and biomedical engineering due to their high elasticity and lightweight. However, to achieve high-performance strain sensors...

Towards the development of anti-infective nanoscale materials employing a photodynamic mechanism of action, we report the synthesis, physical properties (SEM, mechanical strength, water contact angle), spectroscopic characterization (infrared, Raman, DRUV), and evaluation of antibacterial efficacy of porphyrin-conjugated regenerated cellulose nanofibers, termed RC-TETA-PPIX-Zn. Cellulose acetate was electrospun to produce nanofibers, thermally treated to enhance mechanical strength, and finally hydrolyzed to produce regenerated cellulose (RC) nanofibers that possessed a high surface area and nanofibrous structure. Covalent grafting of a protoporphyrin IX (PPIX) photosensitizer using epichlorohydrin/triethylenetetramine (TETA), followed by zinc chelation, afforded RC-TETA-PPIX-Zn. The high surface area afforded by the nanofibers and efficient photosensitizer conjugation led to a very high loading of 412 nmol PPIX/mg material, corresponding to a degree of substitution of 0.1. Antibacterial efficacy was evaluated against Staphylococcus aureus (ATCC-6538) and Escherichia coli (ATCC-8099), with our best results achieving detection limit inactivation (99.999+%) of both bacteria after only 20 min illumination (Xe lamp, λ ≥ 420 nm). No statistically significant loss in antibacterial activity was observed when using nanofibers that had been 'photo-aged' with 5 h of pre-illumination to simulate the effects of photobleaching. Post aPDI, scanning electron microscopy revealed that the bacteria had undergone cell membrane leakage, consistent with oxidative damage caused by photo-generated reactive oxygen species. Taken together, the conjugation strategy employed here provides a scalable, facile and efficient route to creating nanofibrous materials from natural polymers with a high photosensitizer loading, enabling the use of commercially-available neutral porphyrin photosensitizers, such as PPIX, in the design and synthesis of potent anti-infective nanomaterials.

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On-skin electronic systems represent a burgeoning technology that develops wearable devices capable of adapting to the dynamic surfaces of the human body. Present film-based electronics are constrained to single-layered constructions on impermeable substrates that severely inhibit their wearing comfort and multi-functionality. Herein, a thermal-wet comfortable and antibacterial epidermal electrode is hierarchically designed on an ultra-stretchable metafabric. Via the layer-by-layer assembly of trilayered elastomeric fibers with multi-scale sizes and varied compositions, porosity and wettability asymmetries are established across the nonwoven fabric, rendering it with unidirectional liquid conduction and sweat self-pumping performance. The successful printing of stretchable liquid-metal (EGaIn) circuits on ZnO NPs anchored microfibers simultaneously equips the trilayered metafabric with robust antibacterial capability, low-watt heating ability, and high-fidelity detectability for surface electromyography signals of various physical activities. Moreover, the incorporation of thermochromic microcapsules in the outmost fibers also enables the fabric Joule heater with visual indicating ability via reversible color-switching. Thus, this hierarchically engineered epidermal electrode with thermal-wet comfort and antibacterial ability holds great promise in daily applicable healthcare and sports monitoring electronics.