Co-Promoted Ni Nanocatalysts Derived from NiCoAl-LDHs for Low Temperature CO2 Methanation

Ni-based catalysts are prone to agglomeration and carbon deposition at high temperatures. Therefore, the development of Ni-based catalysts with high activities at low temperatures is a very urgent and challenging research topic. Herein, Ni-based nanocatalysts containing Co promoter with mosaic structure were prepared by reduction of NiCoAl-LDHs, and used for CO2 methanation. When the reaction temperature is 250 degrees C (0.1 MPa, GHSV = 30,000 mL center dot g(-1)center dot h(-1)), the conversion of CO2 on the NiCo0.5Al-R catalyst reaches 81%. However, under the same test conditions, the conversion of CO2 on the NiAl-R catalyst is only 26%. The low-temperature activity is significantly improved due to Co which can effectively control the size of the Ni particles, so that the catalyst contains more active sites. The CO2-TPD results show that the Co can also regulate the number of moderately basic sites in the catalyst, which is beneficial to increase the amount of CO2 adsorbed. More importantly, the NiCo0.5Al-R catalyst still maintains high catalytic performance after 92 h of continuous reaction. This is due to the confinement effect of the AlOx substrate inhibiting the agglomeration of Ni nanoparticles. The Ni-based catalysts with high performance at low temperature and high stability prepared by the method used have broad industrial application prospects.

Automated summary

Ni-based nanocatalysts containing Co promoter were prepared and showed significantly improved activity for CO2 conversion at low temperatures. Co effectively controlled the size of Ni particles and regulated the number of basic sites in the catalyst, leading to increased CO2 adsorption. Additionally, the confinement effect of the AlOx substrate inhibited Ni nanoparticles agglomeration, resulting in high stability of the catalyst during continuous reactions.