Decoupling Active Sites for Aqueous-Phase Reforming of Methanol: Efficient CO-Free Hydrogen Production Over a Designed Tandem Pt/Fe5C2:Fe3N@C Catalyst

The development of high-performance catalysts enabling CO-free hydrogen production via aqueous-phase reforming of methanol (APRM) is crucial for integrated methanol-to-hydrogen and hydrogen fuel cell systems. Herein, a tandem Pt/Fe 5 C 2 :Fe 3 N@C catalyst was prepared via a temperature-programmed carbonization-nitridation method followed by photoreduction deposition. Remarkably, the catalyst delivers efficient CO-free H 2 production even at temperatures as high as 210 ° C. The catalyst features a strong metal–support interaction between Pt and Fe 5 C 2 , and a weaker interaction between Pt and Fe 3 N. Mechanistic investigations decouple the functions of the individual components. The carbon support primarily serves to disperse the active components. The Pt–Fe interface provides the active sites for methanol decomposition (CH 3 OH → CO + 2H 2 ). The resulting CO is completely consumed through two subsequent reactions: most undergoes the water–gas shift reaction (CO + H 2 O → CO 2 + H 2 ) on the surfaces of Fe 3 N and Fe 5 C 2 , with Fe 3 N being the dominant active phase, while the remaining trace CO undergoes methanation (CO + 3H 2 → CH 4 + H 2 O), for which Fe 5 C 2 is the principal active site. This synergistic cascade of reactions enables the Pt/Fe 5 C 2 :Fe 3 N@C catalyst to achieve highly efficient CO-free hydrogen production from APRM. This work offers insights into designing catalysts for CO-free hydrogen generation from alcohol-based liquid organic hydrogen carriers and may accelerate the integrated industrialization of the methanol-to-hydrogen and hydrogen fuel cell technology.