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

The performance of CO 2 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 CeO 2 catalysts fabricated via impregnation and electrospinning methods were employed to study the variation of CO 2 methanation performance in terms of the dynamic analysis of intermediates and correlations of oxygen vacancies. The NiNPs@CeO 2 NF catalyst prepared by the co-electrospinning method shows superior catalytic performance with CO 2 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 CeO 2 nanofibers. Additionally, in-situ Raman verified that nanofibers can form more active oxygen vacancies and adsorb well with CO 2 . In-situ DRIFTS analysis reveals that the monodentate and bridging bidentate formate were the key intermediates for CO 2 methanation. • NiNPs@CeO 2 NF catalyst prepared by a novel electrospinning method for CO 2 methanation. • NiNPs@CeO 2 NF 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 CO 2 methanation was revealed by in-situ DRIFTS.