Facet-Engineered Au/α-MoC Catalysts for Low-Temperature Water−Gas Shift Enabling Fuel Cell-Grade Hydrogen

On-site generation of polymer electrolyte membrane fuel cell (PEMFC)-grade hydrogen remains a key barrier to hydrogen energy deployment. Here, we report a facet-engineered Au/α-MoC-R catalyst that enables efficient water−gas shift (WGS) conversion near 353 K. Tailoring α-MoC to preferentially expose the (200) facet creates an Au−MoC(200) interface that promotes H 2 O activation, doubling the reaction rate and improving stability relative to state-of-the-art catalysts. When integrated with methanol steam reforming (MSR) using its waste heat, the coupled system produces hydrogen with less than 10 ppm CO, which is well within the tolerance of PEMFCs, without requiring additional purification. Technoeconomic analysis reveals a ∼30% reduction in operating costs compared with conventional multistage processes. This work demonstrates a single-step, scalable route to high-purity hydrogen, offering a compact and cost-effective pathway for PEMFC-compatible hydrogen production.