Reduced graphene oxide supported Ni-Ce catalysts for CO2 methanation: The support and ceria promotion effects

The reduced oxide graphene (RGO) supported Ni-based catalysts is prepared and modified with ceria (Ni-Ce/ RGO) for CO2 methanation for the first time in the present work, and compared with the active carbon (AC) and gamma-Al2O3 supported samples. The results show that the catalytic activity of the samples without ceria follow the order Ni/RGO > Ni/gamma-Al2O3 > Ni/AC, vs. samples with ceria Ni-Ce/RGO > Ni-Ce/gamma-Al2O3 > Ni-Ce/AC. The activities of all samples were greatly improved after ceria modification. The Ni-Ce/RGO works the best for CO2 methanation, which could reach the highest CO2 conversion of 84.5% and the highest methane yield of 83.0% at 350 degrees C with atmospheric pressure. The excellent catalytic performance of Ni-Ce/RGO could be attributed to the special support effect of RGO and the ceria promotion effect. The support effect of RGO could be attributed to its large surface area and surface oxygen-containing functional groups, which results in stable anchoring of the active metal. The addition of ceria promotes the Ni dispersion on the supports as well as to accelerate the positive reaction due to the oxygen vacancies of ceria.