Faying Fan

Ethylene–vinyl acetate copolymer (EVA) is widely used but limited by its high flammability and smoke emission. Magnesium hydroxide (MH), derived from sustainable Qinghai Salt Lake byproducts, offers a green solution for improving EVA’s fire safety. However, conventional MH suffers from random facet exposure and low efficiency. Here, a facet-engineering strategy is reported to selectively expose the (001) plane of MH by tuning hydrothermal temperature and polyethylene glycol (PEG) content. The optimized MH-3/EVA displays markedly enhanced flame-retardant and smoke-suppression behavior, with the LOI rising from 21.5% to 30.3%, and pHRR, THR, pSPR, TSP reduced by 41.8%, 26.7%, 51.5%, and 33.3%, respectively; Ds,max decreases by 51.1%. The enhanced fire-safety performance is attributed to the tailored surface acid–base sites on the (001)-facet-exposed MH, which capture acidic pyrolysis intermediates and catalyze the deep oxidation of volatile fragments. The synergistic action of CO2 capture, acid–base-catalyzed oxidation, and surface carbonation promotes the formation of a dense MgO/MgCO3/carbon barrier, thereby hindering heat and volatile transfer and inhibiting smoke precursor formation. This study synchronously enhances the flame-retardant and smoke-suppression efficiency of MH in EVA through crystal facet regulation, providing a new approach for the development of sustainable, green, and high-efficiency halogen-free flame-retardant polymer composites with excellent smoke suppression.

Conventional ion separation membranes employed for osmotic energy harvesting rely on nano- or subnanoscale channels that inherently facilitate the transport of hydrated ions, a mechanism that couples ion transport with parasitic solvent flow and fundamentally limits on energy conversion performance. Here, we break this paradigm by constructing continuous NASICON-type Li1.5Al0.5Ge1.5(PO4)3 membranes featuring rigid naked-ion transport channels. At this subnanometer scale, the channels no longer accommodate hydrated ions but enforce complete dehydration, enabling a naked-ion conduction mechanism. This shift eliminates the hydration shell, yielding two transformative outcomes: first, enabling near-ideal Li+ selectivity (transference number t+ ≈ 0.99) via unscreened electrostatic interactions and precise steric exclusion; second, completely decoupling ion transport from water permeation, eradicating the primary source of energy dissipation and achieving 488.6 W·m–2 osmotic energy generation under 200-fold Li+ concentration gradient. Remarkably, this design uniquely leverages impurity counterions in complex brines, boosting the power density over 56-fold to 517 W·m–2 under the 10-fold Li+ concentration gradients. This work establishes naked-ion transport as a foundational and paradigm-shifting design principle for next-generation ion-exchange membranes, opening new avenues for high-efficiency osmotic energy conversion and beyond.

Both the particle size and compositions have a strong influence on the UV-shielding performance of layered double hydroxides (LDHs), and they will interact with each other. To investigate the effects of divalent metal ions on the UV-shielding properties of layered double hydroxides (LDHs), M^II/MgAl–CO₃ LDHs (M = Mg, Co, Ni, Cu, or Zn) with the same primary and secondary particle size have been prepared and their UV-shielding performance have been studied in this work. The UV–vis spectra show that the ZnMgAl-LDHs exhibit the highest absorbance under the ultraviolet B and ultraviolet A rays among these LDH samples, but in the ultraviolet C region, the CuMgAl-LDHs show the highest absorbance and this result is in good accordance with the UV-shielding performance, which was examined by protecting the photocatalytic degradation of rhodamine B aqueous solution. Moreover, under UV rays, PP/ZnMgAl-LDH films show excellent resistance to UV aging, which can be attributed to the strong inhibition of ZnMgAl-LDHs during the production of free radicals in polypropene, as has been confirmed by electron spin resonance results.

The loading of noble-metal nanoparticles (NPs) is an effective approach for the enhancement of H2 sensing performances, although there have been rare reports focused on the effect of the facets of noble-metal nanoparticles in the H2 sensing performance. The catalytic and adsorption performance of noble-metal nanocrystals is mainly determined by their exposed facets, while the gas sensing performance of sensors is strongly correlated to the adsorption and reaction between the gases and sensor materials. Hence, it is very important to study the gas sensing performance of the different facets-exposed noble-metal nanoparticles. In this study, a set of shape-controlled Pd NPs have been prepared and loaded onto the ZnO nanorods, and the gas sensing performance of the Pd nanoparticle-loaded ZnO to 250 ppm of H2 has been detected. The results indicate that the cubic Pd NPs-loaded ZnO shows higher and faster sensing response to H2 than the octahedral and spherical Pd-loaded ZnO owing to the stronger adsorption of the H2 by cubic Pd NPs enclosed by (100) facets than the octahedral NPs enclosed by (111) facets. The cubic Pd NPs-loaded ZnO also exhibits better sensing selectivity and repeatability towards H2.