New insights on the role of YSZ in a NiAl2O4/Al2O3–YSZ catalyst

• YSZ's surface area and charge has a direct influence on interaction metal/support.
• Zr is incorporated only in cubic or defective spinel structures, such as γ-Al2O3 and NiAl2O4.
• YSZ in the NiAl2O4/Al2O3 catalysts is instrumental in diesel catalytic reforming.
• Y2O3 loading in YSZ influences catalyst's activity in diesel steam reforming.
• Catalytic activity reaches its max at 7% (w/w) Y2O3 in YSZ; above this max activity decreases.

Yttria stabilized zirconia (YSZ) role as co-support in alumina (Al2O3) supported Al–Ni spinel (NiAl2O4) was investigated from three perspectives: (a) influence on catalyst morphology, (b) influence on catalyst crystalline phases, and (c) role during diesel steam reforming tests.For the first objective, YSZ surface properties were related to NiAl2O4/Al2O3 morphology. The interaction between these two species was examined using scanning electron microscopy (SEM); surface properties were determined using the multipoint Brunauer, Emmet, and Teller (BET) method for the specific surface area, and mass titration for the zero point charge (PZC) of the surface.The second objective demonstrated, mainly through X-ray diffraction (XRD) analysis, that YSZ enhanced the stabilization of a single Al2O3 phase and inhibited the formation of a metastable aluminates phase.Finally, for the third objective, Y2O3% used to stabilize ZrO2 was varied. Diesel steam reforming tests, using the various YSZ formulations were performed in a fixed-bed reactor setup, with a proprietary diesel–water emulsion mixture at 760 °C. It has been shown that there is a direct dependence of the catalytic activity on the support oxygen vacancies and a maximal Y2O3% was determined.

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