Reaction Pathways of Methanol Reforming over Pt/α-MoC Catalysts Revealed by In Situ High-Pressure MAS NMR

Methanol reforming to hydrogen is a promising route for releasing hydrogen when it is used as a hydrogen carrier, but the reaction pathways are still in dispute. Herein in situ high-pressure MAS NMR rotors have been developed to reveal the reaction pathways of methanol reforming over Pt/α-MoC catalysts. Time-resolved in situ ¹H and ¹³C MAS NMR spectroscopy was carried out to quantitatively monitor the evolution of H₂, CO₂, and reaction intermediates. Notably, for Pt/α-MoC, in addition to CO derived from direct decomposition of methanol proposed for group 10 metal catalysts, formaldehyde is also an active intermediate that readily reacts with methanol or H₂O and further transforms into methyl formate or formic acid, respectively, under high-pressure and lower-temperature conditions. Like the Cu-based catalyst, CO₂ and H₂ were produced mainly through a formic acid mediated mechanism. Moreover, our present work has proven multinuclear high-pressure in situ MAS NMR to be a powerful tool for exploring reactions containing multiple phases (solid, liquid, and gas), and the vital insights related to the reaction mechanism.