Although intensive efforts have been made and great progress has been achieved relating to the electrocatalytic hydrogen evolution reaction (HER), an advanced synthesis strategy for an efficient electrocatalyst is still the most significant goal. In this paper, we introduce PdFeCoNiCu high-entropy alloy (HEA) nanoparticles as an efficient electrocatalyst for the HER, which has been prepared in an oil phase under facile conditions for the first time. PdFeCoNiCu/C shows excellent alkaline HER catalytic performance with an overpotential of only 18 mV and a Tafel slope of 39 mV dec⁻¹. Meanwhile, we achieved the highest mass activity (6.51 A mg_Pd ⁻¹ at −0.07 V vs. RHE) in the alkaline HER among all non-Pt electrocatalysts. PdFeCoNiCu/C also shows surprisingly stable catalytic properties for over 15 days without notable decay. Based on theoretical calculations, the HEA surface demonstrates the optimization of electronic structures based on a synergistic effect between all metals. Pd and Co are confirmed to be the dominant electroactive sites for both H₂ formation and initial water splitting, which are assisted by Ni, Fe, and Cu promotion, enhancing electron transfer and optimizing the binding energies of hydrogen intermediates. This work has supplied significant insight into the design of an efficient electrocatalyst based on HEA materials.

A series of aluminum hypophosphite (AHPi)/graphite-like carbon nitride (g-C₃N₄) (designated as CAHPi) hybrids were prepared, followed by incorporation into thermoplastic polyurethane (TPU). The introduction of CAHPi hybrids into TPU led to a marked reduction in the peak of the heat release rate (pHRR), total heat release, weight loss rate, smoke production rate and total smoke production (TSP). For instance, pHRR and TSP decreased by 40% and 50% for TPU/CAHPi20. Furthermore, the increasing fire growth index and decreasing fire performance index were obtained for TPU/CAHPi systems, suggesting reduced fire hazards. It was found that improved fire safety of TPU nanocomposites was contributed by condensed phase and gas phase mechanisms. On one hand, g-C₃N₄ accelerated the thermal decomposition of AHPi for the formation of more char layers. On the other hand, g-C₃N₄ induced AHPi to generate more free radical capture agents when exposed to flame, besides protecting AHPi against thermal oxidation.