Unlocking Room-Temperature Selective Hydrogenation of 2-Naphthol: Coplanar Adsorption of the Substituted Ring Governs Stepwise Addition of Active Hydrogen toward the Unsubstituted Ring.

A heterogeneous Ru2/Pt1-H-ZSM-5 catalyst achieves regioselective hydrogenation of 2-naphthol into 5,6,7,8-tetrahydro-2-naphthol at 25 °C. Complete conversion and an 81.8% yield are attained, affording a yield rate higher than that of reported homogeneous catalysts. The synergy between the Ru-Pt alloy and acid sites facilitates coplanar adsorption of the electron-rich phenol ring in 2-naphthol via dual hydrogen bonds. Meanwhile, the alloy promotes H2 adsorption and dissociation at bridge sites, directing hydrogenation preferentially to the lower-energy benzene ring in 2-naphthol.