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-CeO2 (CGO) and Al2O3 was studied at 750–900 °C. The order of activity was found to be Rh/CGO > Ni/CGO ∼ Rh/Al2O3 > Ni/Al2O3; we indicated that the comparable activity of Ni/CGO to precious metal Rh/Al2O3 is due to the occurring of gas–solid reactions between hydrocarbons and lattice oxygen (OOx) 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 O2 (as oxidative steam reforming) and H2 adding were further studied over Ni/CGO and Ni/Al2O3. 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 CH4, C2H4 and C2H6 occurred from the thermal decomposition of LPG) to CO and H2. Nevertheless, the addition of too high O2 oppositely decreased H2 yield due to the oxidizing of Ni particle and the possible combusting of H2 generated from the reaction, while the addition of too high H2 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 OOx on the surface of CGO (for the case of Ni/CGO).