(696h) Using CexTi1-XO? Supported Ni for Dry Reforming of Ethane

The dry reforming of alkane reaction is an alternative to the long-established steam reforming technology for producing syngas (H₂ and CO). Additionally, the dry reforming product has a lower H₂:CO ratio compared to steam reforming. It is widely recognized that strong metal-support interaction (SMSI) catalysts are required to overcome the deactivation due to blockage of the active sites by carbon deposition. Therefore, finding a catalyst with an optimized combination of active metal and support is the key to success for DRE.

Ceria supported Ni catalysts were studied DRE, where the unique redox property of Ce³⁺_­­/Ce⁴⁺ changes of the ceria makes it an oxygen sponge while dissociating CO₂ more efficiently. The stability of the oxygen storage capacity can be improved by doping Ti into the ceria lattice. Therefore, a Ce_xTi_1-xO_δ supported Ni catalyst is used for the current study of DRE.

The 2 wt.% Ni loaded Ce_0.7Ti_0.3O_δ is the optimized catalyst, which gives conversions of ethane and CO₂ above 15% after 24 h reaction at 650°C, and the support maintained the same crystal structure as ceria after 24h. TGA-TPO shows less than 10% of the total weight of spent catalyst is attributed to carbon deposition. The combustion temperature of these carbon species is less than 600°C, which indicates the carbon structure is amorphous. The XPS O1s and C1s both gives peaks attributing to different carbon and oxygen bonds, indicating that amorphous carbon can be removed by O^* provided by the support. For XPS Ce3d and Ti2P, Ce³⁺, Ce⁴⁺, Ti³⁺, Ti⁴⁺ peaks are all presented in reduced and spent samples, which indicate that the support has strong reducibility, which is desired for DRE. However, there are two competing products, methane and ethylene. For all catalysts studied, as the time of reaction increases, the selectivity of syngas decreases and ethylene selectivity increases.