Regulating the Electronic Structure via Multi-Transition Metals in Nanoporous High-Entropy Perovskites for Boosted...

High-entropy perovskite oxides (HEPOs) exhibit great application prospects in electrocatalysis due to their enormous compositional design space. Herein, nanoporous La-based HEPOs were synthesized for the first time through a dealloying and annealing strategy, and employed as electrocatalysts for alkaline hydrogen evolution reaction (HER). The HEPOs exhibit single-phase cubic perovskite structures and three-dimensional nanoporous architecture. Among them, L5M-0Cr (La(Ni_0.2Mn_0.2Fe_0.2Co_0.2Ru_0.2)O_3-δ) demonstrates exceptional alkaline HER activity, achieving a low overpotential of ∼50.6 mV at -10 mA cm^{- 2} and a small Tafel slope of ∼60.1 mV dec^{- 1}, surpassing most reported perovskite-based catalysts and exceeding Pt/C at high current densities. Additionally, L5M-0Cr shows remarkable stability over 120 h of continuous operation and delivers promising performance in overall water-splitting systems. Structural characterizations, in situ Raman spectroscopy, and density functional theory (DFT) calculations reveal that lattice distortion and charge redistribution within high-entropy systems can effectively modulate electronic structure, inducing strong hybridization between Ru 4d and O 2p orbitals. Theoretical simulations are employed to establish the volcano-type correlation between hydrogen adsorption free energy (ΔG_*H) and HER exchange current density (log i₀). This work demonstrates that high-entropy design synergistically optimizes the structural, electronic, and catalytic properties of perovskites, providing a promising strategy for developing efficient electrocatalysts in energy conversion applications.