Study On Nanoarchitecture Ni/ZrO₂ Catalysts In The Steam Reforming Of Ethanol For Hydrogen Production

Producing hydrogen from steam reforming of bio-ethanol has been extensively investigated for the fuel cell applications, since the feed can be produced from renewable resource and producing H₂-rich mixture with high system energy efficiency. Developing a Ni-based catalyst with high activity and good stability, which was just this work point to, can help commercializing the important route for hydrogen production.Zirconia powders with particle size of about 50 nm, 25 nm and 10 nm respectively, were prepared in chemical precipitation method. Nanoarchitecture Ni/ZrO₂ catalysts in which comparable sized metal and oxide domains are networked are prepared in wetness impregnation method. Catalysis activity and durability in the SRE process are tested in a fixed micro-reactor system. The catalysts are characterized to provide useful information for a further study with this new style catalysts.TEM photographs showed that the oxide particles are larger than metal particles in factors of 6, 2 and 1 respectively in the NZ-1, NZ-2 and NZ-3 catalysts. H₂-TPR profiles suggested that the interaction between metal and oxides are strengthened when the size of the oxide particle get closer to the metal particle size in the catalyst.The 150 h duration test revealed that the nanoarchitecture Ni/ZrO₂ catalysts could indeed convert the ethanol solution into H₂-rich mixture with high activity and good stability. 4.5 mol H₂ accompanied with 1.0 mol CO2, 0.9 mol CO and 0.1 mol CH4 were produced by NZ-1, NZ-2 and NZ-3 catalysts separately for per mole ethanol inlet into the system. Another decay experiment operated in higher space velocity showed a best catalysis stabiliy on the catalyst NZ-3.TG analysis revealed that comparable coke were deposited on the three catalysts tested in the 150 h experiment, and the NZ-2 have more complex carbon species. XRD patterns indicated that the strong interaction between metal and oxide helps the catalysis stability of the catalyst.