The Influence of the ZrO 2 Crystal Phase on Cu/ZrO 2 -Al 2 O 3 Catalysts in Methanol Steam Reforming.

Copper-based catalysts are widely used in methanol steam reforming to produce hydrogen. In this paper, the supportive effect of the crystal phase of ZrO₂ on Cu-based catalysts in methanol steam reforming is discussed. Monoclinic(m-), Tetragonal(t-) and mixed ZrO₂ phases were prepared, and structure–activity relationships were investigated with XRD, H₂-TPR, BET, HR-TEM and XPS. It was found that the catalyst with a 81.4% monoclinic ZrO₂ crystal phase exhibited the highest methanol conversion (88.5%) and the highest hydrogen production rate (104.6 μmol/g_cat·s) at 275 °C as it displayed the best reducing properties and more oxygen vacancies on the catalyst surface. Oxygen vacancies can produce more Cu¹⁺ + Cu⁰, which is the active species for methanol steam reforming on the catalyst surface, and therefore affect catalytic activity. [ABSTRACT FROM AUTHOR]