Decoupling ActiveSites for Aqueous-Phase Reformingof Methanol: Efficient CO-Free Hydrogen Production Over a DesignedTandem Pt/Fe5C2:Fe3N@C Catalyst

Abstract 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/Fe5C2:Fe3N@C catalyst was prepared via a temperature-programmed carbonization-nitridation method followed by photoreduction deposition. Remarkably, the catalyst delivers efficient CO-free H2 production even at temperatures as high as 210 °C. The catalyst features a strong metal–support interaction between Pt and Fe5C2, and a weaker interaction between Pt and Fe3N. 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 (CH3OH → CO + 2H2). The resulting CO is completely consumed through two subsequent reactions: most undergoes the water–gas shift reaction (CO + H2O → CO2 + H2) on the surfaces of Fe3N and Fe5C2, with Fe3N being the dominant active phase, while the remaining trace CO undergoes methanation (CO + 3H2 → CH4 + H2O), for which Fe5C2 is the principal active site. This synergistic cascade of reactions enables the Pt/Fe5C2:Fe3N@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.