Facet‐Dependent Solid Frustrated Lewis Pairs on Co ₃ O ₄ Catalysts Towards Semi‐Hydrogenation Reaction of Alkynols

Abstract

Abstract The semi‐hydrogenation of alkynols to enols represents a vital industrial reaction for fine chemical synthesis, yet developing highly selective non‐noble metal catalysts remains an urgent challenge. Herein, we report a Co 3 O 4 nanorod (Co 3 O 4 ‐NR) catalyst with abundant solid‐frustrated Lewis pairs (SFLPs) on specifically exposed {110} facets, where coordinatively unsaturated Co 2+ acts as Lewis acid site whilst the surface hydroxyl group serves as Lewis base site. The Co 3 O 4 ‐NR catalyst exhibits exceptional performance toward semi‐hydrogenation from 3‐butyn‐1‐ol to 3‐buten‐1‐ol with a product yield of 88.2%, which is preponderate to other non‐noble metal catalysts. Poisoning experiments, in situ DRIFTS and theoretical calculations verify that the SFLPs sites serve as intrinsic active centers for H 2 activation/dissociation and substrate adsorption. The hydrogenation of key intermediate (C 4 H 7 O*) is identified as the rate‐determining step, where H δ+ species strongly tethered to surface −OH group suppresses over‐hydrogenation and thereby enhances the semi‐hydrogenation selectivity. Projected density of states (PDOS) analysis reveals an accelerated hydrogenation kinetics via d – p orbital hybridization between Co 3 d orbitals and C 2 p orbitals in C 4 H 7 O*. This work advances the design of efficient and cost‐effective SFLPs‐based heterogeneous catalysts, which shows potential application in the synthesis of fine chemicals.