Highly stable low noble metal content rhodium-based catalyst for the dry reforming of methane

The catalytic performance of different nickel- and rhodium-based catalysts supported on gamma-Al2O3 was investigated for the dry reforming of methane (DRM) reaction. The catalysts were prepared either by the incipient wetness impregnation method (IWI) or urea precipitation method (UPM) and characterized by XRD, TPR, XRF, BET, and H-2 chemisorption techniques. Long-term reactions were performed in a fixed bed reactor over the temperature range of 700-800 degrees C, WHSV 12-108 h(-1), and with a CH4:CO2 feed ratio equal to unity. All nickel-based catalysts tested, despite presenting high CH4 and CO2 conversions in the first reaction moments, underwent deactivation and long-term performance losses. On the other hand, a low rhodium content tested catalyst, 0.1%Rh/Al2O3, exhibited a remarkable performance with CH4 and CO2 conversions compatible with the thermodynamic conversions and an H-2/CO ratio close to 1. Moreover, the catalyst presented exceptional stability with no visible signs of deactivation over more than 180 h on stream. Therefore, the aforementioned catalyst represents an important contribution to the dry reforming of methane technology, since it exhibited high conversions, exceptional stability, and very low noble metal content.