Regulating stereoselectivity in polycyclic aromatics hydrogenation via metal–support interface engineering

Abstract Thermodynamically dictated inherent stereo‐limitation makes directional tuning of cis / trans products during polycyclic aromatic hydrocarbon hydrogenation extremely tough, and no unified interfacial regulation method can realize bidirectional inversion of stereoselectivity so far. Here, we discover an unprecedented inverse stereoregulation effect induced by isostructural M–O–Ce (M = Ru, Pd) interfacial sites constructed on CeO 2 support. Modulating interfacial concentration linearly boosts cis‐ decalin formation for Ru/CeO 2 yet promotes trans‐ decalin generation for Pd/CeO 2 , delivering record cis / trans = 6.09 and trans / cis = 2.60, respectively. Mechanism identification unveils decoupled functions of metallic sites and interfacial species, where metal sites afford hydrogenation activity and M–O–Ce interfaces serve as exclusive stereoselective switchers. The positive correlation between metal–support interfacial electron transfer and stereoisomeric pathway barrier is identified, uncovering the intrinsic electronic origin of opposite stereochemical preference. The developed interfacial engineering methodology is generalizable for stereocontrolled hydrogenation of various functionalized PAHs, opening a facile route for PAH stereoselective hydrogenation.