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.