Spin-state-regulated dual-metal orbital engineering in heterostructured nanosheets for d-band center-optimized...

A dual-metal orbital engineering strategy is developed to synergistically optimize active site reactivity and bulk-phase stability through precise d-band center modulation and enhanced charge transfer kinetics. Specifically, a flower-like NiMn selenide nanoarchitecture, modified with silver nanoparticles and sulfur-doped carbon quantum dots (Ag/NiSe₂/MnSe/S-CQDs), is fabricated via controlled spin state regulation. The asymmetric configuration between NiSe₂ and MnSe induces a significant elevation in the energy levels of Ni's e_g and t_2g orbitals, thereby optimizing intermediate conductivity, e_g orbital electron occupancy, and adsorption free energy. Simultaneously, the reduced energy levels of Mn's e_g and t_2g orbitals strengthen the interaction between Ni 3d/Mn 3d and Se 2p orbitals, promoting synergistic coupling, optimizing the electronic structure, and ensuring electrocatalytic stability. Consequently, the optimized catalyst exhibits remarkable performance, requiring overpotentials of 54.0 ± 0.5 mV and 235.0 ± 0.5 mV for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, at 10 mA cm^-2, while maintaining excellent stability. This work establishes a universal paradigm for d-band center manipulation in electrocatalyst design, providing critical insights for developing advanced energy conversion systems.