Highly stable hydrothermal Cu-Zn oxide catalysts for low-temperature methanol steam reforming in structured reformers for fuel-cell applications

Methanol steam reforming (MSR) was investigated over binary Cu-Zn mixed oxide catalysts prepared hydrothermally. Among the catalysts synthesized at different hydrothermal and calcination temperatures, HTM120 (120 °C hydrothermal treatment, 300 °C calcination) exhibited the most favorable combination of surface area, crystallite size and Cu-ZnO x interfacial characteristics, enabling high MSR activity around and below 200 °C. Seven independently prepared HTM120 batches yielded 97.0 ± 0.5% methanol conversion at 220 ο C. Under matched reactor conditions, HTM120 performed at least comparably to commercial HiFUEL R120. HTM120 retained 94.4% of its initial calculated H 2 productivity after 487 h time-on-stream and 30 startup/shutdown runs, while methanol conversion remained above 93%. In-situ MSR-DRIFTS revealed methoxy and formate surface species consistent with a methoxy-formate reaction sequence toward CO 2 and H 2 formation, with low CO production. These results identify hydrothermally Cu-Zn mixed oxides as promising catalysts for low-temperature structured methanol reformers for fuel-cell applications.