Combined In Situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy and Kinetic Studies on CO2 Methanation Reaction over Ni/Al2O3

Supported Ni/Al(2)O(3 )catalysts with different loadings were prepared via the precipitation-impregnation method . The catalyst structure is characterized by N(2 )adsorption-desorption, XRD, quasi in situ XPS, H-2 -TPR, CO-TPR, CO2-TPD, and pulsed N2O titration. Based on in situ DRIFTS and kinetic analysis, a dominant reaction pathway is proposed, involving Ni0 and Ni-Al(2)O(3 )interfacial sites as the active sites. Ni0 promotes the dissociation of hydrogen into *H, while the Ni-Al(2)O(3 )interface facilitates the activation of CO2 into *CO followed by the migration of *CO to Ni0 sites and the subsequent hydrogenation into CH4 . In addition, the hydrogenation of *CO into CH4 is considered to be the slow step for the CO2 methanation reaction.

Automated summary

Based on experimental and analytical studies, it was found that Ni0 and Ni-Al(2)O(3) interface sites are the active sites of the catalyst, promoting the activation of hydrogen and CO2, and ultimately leading to the methanation reaction.