Comparative Study Of Ni-based Mixed Oxide Catalyst For Carbon Dioxide Reforming Of Methane

摘要

Carbon dioxide reforming of methane (CDRM) to synthesis gas was studied over various Ni-based catalysts. It is shown that the mixed oxide supports CeO_2-ZrO_2, CeO_2-Al_2O_3, and La2O_3-Al_2O_3, prepared using surfactant, exhibit a high catalytic activity and stability for CDRM. Temperature program reduction (TPR) results demonstrate that the presence of CeO_2, ZrO_2, or La_2O_3 leads to the enhancement of the Ni reducibility compared to Al_2O_3, which is an important indicator of high activity and stability of these Ni catalysts for CDRM. Our thermodynamic calculations indicate that CeO_2 could react with CH_4 to produce synthesis gas, and then CO_2 might reoxidize CeO_(2-x) to its oxidation state. Furthermore, CeO_2 might help in gasification of deposited carbon to inhibit the carbon formation and therefore improve catalyst stability. The presence of alumina tends not to affect the stability of the catalyst as well.