Ni nanoparticles enclosed in highly mesoporous nanofibers with oxygen vacancies for efficient CO2 methanation

The performance of CO2 methanation has critical relationships with oxygen vacancies, thus the fundamental insights of oxygen vacancies activation are of great importance. Herein, a series of Ni-based CeO2 catalysts fabricated via impregnation and electrospinning methods were employed to study the variation of CO2 methanation performance in terms of the dynamic analysis of intermediates and correlations of oxygen vacancies. The NiNPs@CeO2NF catalyst prepared by the co-electrospinning method shows superior catalytic performance with CO2 conversion of 50.6 % and 82.3 % at the low temperature of 250 °C and 300 °C, respectively, as well as excellent stability of 60 h at a high temperature of 400 °C. The achieved catalytic properties could be attributed to the confined environment and synergistic effect between Ni nanoparticles and CeO2 nanofibers. Additionally, in-situ Raman verified that nanofibers can form more active oxygen vacancies and adsorb well with CO2. In-situ DRIFTS analysis reveals that the monodentate and bridging bidentate formate were the key intermediates for CO2 methanation. [Display omitted] •NiNPs@CeO2NF catalyst prepared by a novel electrospinning method for CO2 methanation.•NiNPs@CeO2NF catalyst performs excellent activity due to the synergistic effect between NiNPs and nanofibers.•The dynamic progress of oxygen defects was recorded by in-situ Raman.•The key intermediate of formate for CO2 methanation was revealed by in-situ DRIFTS.