Development of a Ni-Ce_0.8Zr_0.2O₂ catalyst for solid oxide fuel cells operating on ethanol through internal reforming

Inexpensive 20 wt.% Ni-Ce_0.8Zr_0.2O₂ catalysts are synthesized by a glycine nitrate process (GNP) and an impregnation process (IMP). The catalytic activity for ethanol steam reforming (ESR) at 400-650 °C, catalytic stability and carbon deposition properties are investigated. Ni-Ce_0.8Zr_0.2O₂ (GNP) shows a higher catalytic performance than Ni-Ce_0.8Zr_0.2O ₂ (IMP), especially at lower temperatures. It also presents a better coking resistance and a lower graphitization degree of the deposited carbon. The superior catalytic activity and coke resistance of Ni-Ce_0.8Zr _0.2O₂ (GNP) is attributed to the small particle size of the active metallic nickel phase and the strong interaction between the nickel and the Ce_0.8Zr_0.2O₂ support, as evidenced by the XRD and H₂-TPR. The Ni-Ce_0.8Zr_0.2O ₂ (GNP) is further applied as an anode functional layer in solid oxide fuel cells operating on ethanol steam. The cell yields a peak power density of 536 mW cm^-2 at 700 °C when operating on EtOH-H ₂O gas mixtures, which is only slightly lower than that of hydrogen fuel, whereas the cell without the functional layer failed for short-term operations. Ni-Ce_0.8Zr_0.2O₂ (GNP) is promising as an active and highly coking-resistant catalyst layer for solid-oxide fuel cells operating on ethanol steam fuel.