Atomic Orbital-Driven SERS Enhancement Via D-Band Engineering in High-Entropy Alloy Aerogels

Understanding atomic orbital-level interactions at material-molecule interfaces is crucial for advancing surface-enhanced Raman spectroscopy (SERS). While conventional mechanisms focus on electromagnetic effects or interfacial charge transfer (CT), the role of orbital hybridization in multimetallic systems remains underexplored. Here, a d-band-mediated CT mechanism is proposed through the engineering high-entropy alloy aerogels (HEAAs). A face-centered cubic AuAgCuMnInBi HEAAs synthesized via one-step coreduction achieves ultrasensitive SERS detection of crystal violet. Density of states analyses reveal that Mn-3d orbitals bridge electron reservoirs (Au/Ag/Cu) and In/Bi-p orbitals, enabling efficient charge delocalization. Voltage-tunable SERS signals in MnInBi subsystems confirm d-band-dependent CT enhancement. Beyond molecular sensing, this mechanism allows direct capture of reactive intermediates (OH·, O 2 · – ) and 5 n M uranium detection, bridging SERS enhancement dynamics with catalytic pathway elucidation. These findings establish d-band engineering as a paradigm for designing multifunctional SERS substrates, bridging atomic-scale electronic interactions with ultrasensitive sensing and catalytic mechanism elucidation.