Effect of CeO2 on carbon deposition resistance of Ni/CeO2 catalyst supported on SiC porous ceramic for ethanol steam reforming

Ni/CeO 2 catalysts ( n CeO2 : n Ni  = 0, 1, 4, 7, 10) supported on SiC porous ceramics for ethanol steam reforming (ESR) were investigated with respect to hydrogen production performance and growth of carbon deposition. The oxygen released from CeO 2 enables the oxidation of CH x species to serve as carbon precursors, thus providing Ni/CeO 2 catalysts with stronger resistance to carbon deposition compared with Ni catalysts. The Ni/CeO 2 catalysts prepared by inverse microemulsion and impregnation methods exhibit regular semicircular spherical shape on SiC porous ceramics. Under 500 °C for 25 h of ESR reaction, the ethanol conversion rate over Ni/CeO 2 catalysts ( n CeO2 : n Ni  = 7) is sustained up to 100% and H 2 selectivity is essentially kept at 74%. The by-product selectivity declines stepwise with increasing content of CeO 2 , which is attributed to the adsorption and oxidation of CO and of CH x species as CH 4 precursor from CeO 2 . The scanning electron microscopy (SEM) and transform electron microscopy (TEM) results reveal that further loading of CeO 2 on the surface of Ni catalysts can alleviate both migration and sintering of Ni particles. Furthermore, carbon deposition on Ni/CeO 2 catalysts preferentially outgrow filamentous rather than amorphous carbon , with a tendency for the latter to be more deactivated.