Steam reforming of LPG over Ni and Rh supported on Gd-CeO2 and Al2O3: Effect of support and feed composition

The steam reforming of liquefied petroleum gas (LPG) over Ni- and Rh-based catalysts supported on Gd-CeO(2) (CGO) and Al(2)O(3) was studied at 750-900 degrees C. The order of activity was found to be Rh/CGO > Ni/CGO similar to Rh/Al(2)O(3) > Ni/Al(2)O(3); we indicated that the comparable activity of Ni/CGO to precious metal Rh/Al(2)O(3) is due to the occurring of gas-solid reactions between hydrocarbons and lattice oxygen (O(O)(x)) on CGO surface along with the reaction taking place on the active site of Ni, which helps preventing the carbon deposition and promoting the steam reforming of LPG. The effects of O(2) (as oxidative steam reforming) and H(2) adding were further studied over Ni/CGO and Ni/Al(2)O(3). It was found that the additional of these compounds significantly reduced the amount of carbon deposition and promoted the conversion of hydrocarbons (i.e., LPG as well as CH(4), C(2)H(4) and C(2)H(6) occurred from the thermal decomposition of LPG) to CO and H(2). Nevertheless, the addition of too high O(2) oppositely decreased H(2) yield due to the oxidizing of Ni particle and the possible combusting of H(2) generated from the reaction, while the addition of too high H(2) also negatively affect the catalyst activity due to the occurring of catalyst active site competition and the inhibition of gas-solid reactions between the gaseous hydrocarbon compounds and O(O)(x) on the surface of CGO (for the case of Ni/CGO). (C) 2010 Elsevier Ltd. All rights reserved.