| Summary: | 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 CO<sub>2</sub> methanation. When the reaction temperature is 250 °C (0.1 MPa, GHSV = 30,000 mL·g<sup>−1</sup>·h<sup>−1</sup>), the conversion of CO<sub>2</sub> on the NiCo<sub>0.5</sub>Al-R catalyst reaches 81%. However, under the same test conditions, the conversion of CO<sub>2</sub> 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 CO<sub>2</sub>-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 CO<sub>2</sub> adsorbed. More importantly, the NiCo<sub>0.5</sub>Al-R catalyst still maintains high catalytic performance after 92 h of continuous reaction. This is due to the confinement effect of the AlO<sub>x</sub> 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.
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