Exploring the influence of nickel precursors on constructing efficient Ni-based CO₂ methanation catalysts assisted with in-situ technologies

In this work, a series of Ni-based CO2 methanation catalysts were prepared with different nickel salt precursors. The Ni-AA catalyst with nickel acetylacetonate precursor displayed the highest activity among these catalysts. The in-situ diffused reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS) and the online-tandem thermogravimetric mass spectrometry (TG-MS) were performed to investigate the intermediates of the catalyst calcination process. The superior performance of the Ni-AA catalyst could be derived from its special coordinating anion. Furthermore, the rapid deactivation of the Ni-S catalyst with nickel sulfate precursor was attributed to the generation of the Ni3S2 after reduction pretreatment. As for the Ni-Cl catalyst with nickel chloride precursor, its negligible activity could be owing to poisoning effect of the Cl- by the coverage of the catalyst surface. Therefore, the significant role of the metal salt precursor should be preferentially considered when designing the Ni-based catalysts and even other metal based heterogeneous catalysts.