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

Abstract 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.