Dry Reforming of Methane over Ni-Fe-Al Catalysts Prepared by Solution Combustion Synthesis

Abstract

Dry reforming of methane (DRM) is a promising method to utilize two greenhouse gases, such as CH4 and CO2, to produce synthesis gas. In the current work, both monometallic Ni and bimetallic Ni-Fe catalysts with different Fe/Ni molar ratios, synthesized by solution combustion synthesis (SCS) in DRM, were investigated using a feed ratio of CH4/CO2/Ar of 1:1:1 at 600-900 °C. The catalysts were characterized by several physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy energy-dispersive X-ray (SEM-EDX) spectroscopy, transmission electron microscopy (TEM), CHNS, N2 physisorption, H2-TPR, O2-TPO, NH3-TPD, and thermogravimetric analysis (TGA). One of the highest hydrogen yields of 81% was obtained at 93% conversion of CH4 and 94% conversion of CO2 for the bimetallic 15Ni-5Fe-30Al catalyst, which contained, according to XRD, NiAl2O4 spinel and metallic Ni phases. The spinel phase was decomposed during the reaction, while the Ni3Fe alloy was formed. Catalysts with a higher Fe/Ni ratio exhibited lower conversion and contained an inactive FeAl2O4 spinel. Rather stable yields of CO and H2 were obtained in an experiment with 20 h time-on-stream.