Entropy-Mediated Gradient Oxygenophilic Architecture on High-Entropy Alloy for Dynamic Spillover and Bifunctional...

Breaking scaling relations and overcoming kinetic limitations in multistep hydrogen electrocatalysis remains a fundamental challenge. In this work, we designed and synthesized a high-entropy alloy catalyst comprising Ir, Ru, Mo, W, and Cu supported on nitrogen-doped carbon spheres. This unique structure creates active sites with a quasi-continuous distribution of binding energies for H* and OH* intermediates. Density functional theory (DFT) calculations confirm that the random spatial arrangement of sites enables low-energy-barrier spillover pathways for H* and OH* (χ_H* ^max = 0.27 eV; χ_OH* ^max = 0.61 eV), while continuous d-orbital coupling facilitates efficient electron transfer. This design enables each elementary step of hydrogen oxidation and evolution reactions (HOR/HER) to be directed to a site with favorable energetics. As a result, it exhibits exceptional bifunctional performance with a HOR mass activity of 8.83 A mg^-1 and an HER overpotential of only 11 mV at 10 mA cm^-2, significantly outperforming commercial Pt/C_com and previously reported catalysts. Operando spectroscopy and DFT analyses reveal that the gradient energy landscape promotes dynamic intermediate spillover, preventing site blocking and enhancing reaction kinetics. This work establishes a universal design strategy develop high-performance electrocatalysts that transcend conventional Sabatier principle limitations.