Preparation of gadolinia doped ceria via metal complex decomposition method: Its application as catalyst for the steam reforming of ethane

摘要

The ceria (CeO2) and gadolinia doped ceria (GDC; Ce_(1-x)Gd_xO_(2-δ)with x = 0.10,0.15, and 0.20) catalysts were successfully prepared via metal complex decomposition method at 900 °C for 2 h. The synthesized CeO2 and GDC were found to have useful activity to convert ethane to syngas via the steam reforming reaction at the temperature range of 800-900 °C. The catalytic activity was improved with increasing Gd doping amount from 0 to 0.1 and 0.15; nevertheless, at higher Gd doping content (0.2), the improvement becomes less pronounced. Among all catalysts, Ce_(0.85)Gd_(0.15)O_(2-δ) showed the best steam reforming activity; furthermore, the amount of carbon formation over this catalyst was relatively low. These enhancements are mainly due to the high specific surface area and the good oxygen storage capacity (OSC) of the material. During the steam reforming process, the gas-solid reactions between the gaseous components presented in the system (C2H6, C2H4, and CH4) and the lattice oxygen (O_x) on the surface CeO2 or GDC occurs. The reactions of hydrocarbons adsorbed on the surface with O_x (C_nH_m + O_x → nCO + m/2(H2) + O_(x-n)) can prevent the formation of carbon species from hydrocarbons decomposition reaction (C_nH_m <=> nC + m/2H2). Moreover, the formation of carbon via Boudouard reaction (2CO<= >CO2 + C) is also reduced by the gas-solid reaction of CO with the lattice oxygen (CO + O_x <=> CO2 + O_(x-1)).