Phase Engineering of Mg–Pt Intermetallic Hydrogenation Catalysts for CO Poisoning Resistance

Platinum group metals (PGMs) are efficient catalysts for industrial hydrogenation reactions but are extremely sensitive to CO (ppm levels), making the direct utilization of industrial crude hydrogen containing CO infeasible. Herein, we report the phase engineering of Mg-Pt intermetallic catalysts achieved through the precise control of reactive metal-support interactions (RMSIs) between Pt nanoparticles (NPs) and Mg supports. By manipulating Pt crystallinity, we synthesized two distinct phases, Mg₂₉Pt₄ and Mg₃Pt. In the presence of CO, Mg₂₉Pt₄ demonstrates remarkable activity for selective hydrogenation reactions, contrasting sharply with the almost complete deactivation of metallic Pt. Notably, Mg₂₉Pt₄ retains ∼88% of its original activity when exposed to 0.2 vol% CO, a typical industrial crude hydrogen concentration, outperforming state-of-the-art Pt catalysts. This superior CO tolerance arises from its electron-rich Pt sites and low d-band center, which suppress electron donation from CO 5σ orbitals to Pt 5d orbitals while hindering electron back-donation from Pt d orbitals to CO 2π* antibonding orbitals. Moreover, Mg₂₉Pt₄ also facilitates the hydrogenation of diverse functional groups, including alkynes, aldehydes, and nitroarenes, while maintaining excellent CO tolerance. This work demonstrates that manipulating the electronic properties of Pt single-atom sites can alter CO adsorption behavior, enabling the design of efficient Pt catalysts for anti-CO poisoning.