A High-Productivity and Near-Zero-CO Cu-Based Spinel/CeO2 Catalyst for On-Board Hydrogen Generation: Towards Sustainable Future Marine Fuels

In the current situation of carbon reduction in the shipping industry, hydrogen as a future energy source is the key to hydrogen-powered ships. Onboard methanol steam reforming (MSR) hydrogen production technology is of great significance in solving the hydrogen safety issues of hydrogen-powered ships. The key to this technology is to obtain MSR catalysts with lower CO selectivity and higher hydrogen production performance for use as hydrogen sources in high-temperature proton-exchange membrane fuel cells (HT-PEMFCs). A new Cu0.75Mg0.25Ga0.7Fe1.3O4 spinel catalyst was synthesized and subsequently dispersed at a nominal loading of 15 wt% onto three distinct oxide supports: CeO2, ZrO2, and Cr2O3. The synthesized samples were characterized, and their catalytic behavior in MSR was evaluated in a fixed-bed reactor. The results establish that the loading procedure leaves the bulk spinel structure intact. Among the series, the CeO2-supported specimen exhibits a higher degree of active-phase dispersion, a loosely packed and highly porous architecture, and more extensive interfacial contact between the spinel crystallites and the support. Relative to its ZrO2- and Cr2O3-supported counterparts, Cu0.75Mg0.25Ga0.7Fe1.3O4@CeO2 delivers markedly superior overall catalytic performance. Under conditions of 320 °C, a water-to-methanol molar ratio of 3:1, and a liquid hourly space velocity (LHSV) of 15 h−1, complete methanol conversion (100%) is achieved, together with a hydrogen production rate of 8.71 mmol·min−1·gcat−1 and CO selectivity approaching zero. The outstanding catalytic behavior may be attributed to the interface synergy between the spinel active center and CeO2 support, particularly the synergistic effect of oxygen vacancies and Ce4+/Ce3+ redox shuttle, which facilitates substrate replacement while inhibiting CO production. This catalyst architecture provides a promising material platform for on-line methanol reforming integrated with fuel cell power systems on hydrogen-powered ships.