Effects of La2O3 on ZrO2 supported Ni catalysts for autothermal reforming of CH4

Abstract

The effect of La2O3 content in Ni-La-Zr catalyst was investigated for the autothermal reforming (ATR) of CH4. The catalysts were prepared by the coprecipitation method and had a mesoporous structure. Temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) indicated that a strong interaction developed between Ni species and the support with the addition of La2O3. Thermogravitnetric analysis (TGA) and H-2-pulse chemisorption showed that the addition of La2O3 led to well dispersed NiO molecules on the support. Ni-La-Zr catalysts gave much higher CH4 conversion than Ni-Zr catalyst. The Ni-La-Zr containing 3.2 wt% La2O3 showed the highest activity. The optimum conditions for maximal CH4 conversion and H-2 yield were H2O/CH4=1.00, O-2/CH4=0.75. Under these conditions, CH4 conversion of 83% was achieved at 700 degrees C. In excess O-2 (O-2/CH4>0.88), the catalytic activity was decreased due to sintering of the catalyst.