Abstract
Developing an efficient catalyst is essential to converting liquid hydrocarbon fuels to hydrogen by steam reforming technology. A series of Pt modified Ni/Al2O3 catalysts were employed in steam reforming of n-dodecane as surrogate liquid hydrocarbon fuels. The properties of fresh and spent catalysts were investigated employing X-ray diffraction (XRD), H-2 temperature programmed reduction (H-2-TPR), Transmission Electron Microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray adsorption fine structure analysis (XAFS), thermogravimetric analysis (TGA), and Raman spectroscopy. Characterization of fresh catalysts indicated the presence of NiPt alloy in these Pt modified catalysts, leading to smaller particle size and more moderate metal-support NiO species. The conversion over these Pt modified Ni/Al2O3 catalysts was enhanced at least three fold compared with Ni/Al2O3 catalyst, H-2 molar yield over NiPt1.0/Al2O3 is as high as fivefold compared with that of Ni/Al2O3, and that no obvious deactivation for steam reforming of n-dodecane over NiPt1.0/Al2O3 was observed in 25 h reaction time. TGA and Raman spectra of spent catalysts results revealed that the addition of Pt suppressed coking formation effectively through forming amorphous carbon, which leads to enhanced coking resistance as observed on Pt modified catalysts.