4f-Electron-Regulated Dual-Periodic Bonding Evolution Across the Lanthanide Series

Lanthanide-based catalysts have attracted increasing attention due to their unique electronic structures, yet the relationship between 4f electron evolution and catalytic behavior remains unclear. Here, using structurally uniform lanthanide single-atom catalysts as a model platform, we systematically investigate the influence of 4f electron filling on bonding evolution across the lanthanide series. We reveal a dual-periodic trend in lanthanide-support binding energies and adsorbate bonding energies, which increases from La to Eu and from Gd to Yb. This behavior originates from progressive electron redistribution between 5d and 4f orbitals, which modulates the electron population of bonding orbitals. The half-filled 4f⁷ configuration induces an abrupt transition between Eu and Gd. Furthermore, similar crystal-field splitting enables robust linear relationships between binding and bonding energies across diverse coordination environments. More importantly, the persistence of these electronic characteristics across diverse coordination environments demonstrates that the dual-periodic evolution represents an intrinsic feature of lanthanide chemistry rather than a system-specific phenomenon. These findings establish a 4f-electron-regulated bonding framework for understanding lanthanide reactivity and guiding catalyst design.