Combining multiple metal elements into one nanostructure merits untold application potential but is still a challenge for the traditional bottom-up synthesis method. Herein, we propose a eutectic-directed self-templating strategy to prepare two multi-component nanostructured alloys (PtPdRhIrNi (D-SN) and NiPtPdRhIrAl (D-SS)) through the combination of rapid solidification with dealloying. The PtPdRhIrNi nanoporous nanowires (NPNWs) represent a new family of high-entropy alloys (HEAs) containing delicate hierarchical nanostructure with ultrafine ligament sizes of ~ 2 nm in addition to one-dimensional (1D) morphology. Moreover, the PtPdRhIrNi NPNWs display excellent electrocatalytic activity and stability toward hydrogen evolution reaction, with the low overpotential of 22 and 55 mV to afford a current density of 10 mA·cm⁻² in 0.5 M H₂SO₄ and 1.0 M KOH electrolytes, respectively. The enhanced electrocatalytic performance can be attributed to the high-entropy effect favoring the surface electronic structure for the optimized activity, the promotion impact of Ni, 1D morphology facilitating the electron transport, and the nanoporous structure promoting the electrolyte diffusion.

The thermal stability of CeO₂ nanomaterials can directly impact both the uniformity of the supported catalysts and the catalytic behavior of CeO₂ itself. However, knowledge about the thermal stability of CeO₂ is still deficient. Here, we conduct in-situ transmission electron microscopy experiments and theoretical calculations to elucidate the thermal stability of CeO₂ nanomaterials under different environments. A sinter (< 700 ℃) and a structural decomposition (> 700 ℃) are observed within CeO₂ nanoflowers under O₂. The sinter firstly occurs among the nanoflowers' monomers and then the sintered nanoparticles structurally decompose to tiny nanoparticles from the strain interface. Under a vacuum environment, the CeO₂ nanoflowers firstly undergo a transition from cubic fluorite CeO₂ to hexagonal Ce₂O₃, accompanied by the oxygen release. The Ce₂O₃ nanoparticles further atomically sublimate from the edges to the center under high temperatures. Theoretical calculation results reveal a considerably lower energy barrier for the structural decomposition under O₂ and for the sublimation under vacuum. This work provides a perspective on the structural design and performance optimization of CeO₂-based catalysts.