Identifying the key structural features of Ni-based catalysts for the CO2 methanation reaction

Abstract

Identifying the parameters influencing the selectivity of products is prominently significant for fabricating efficient catalysts. However, little progress has been made in describing the regulation rule of CH₄ selectivity toward the CO₂ methanation reaction, which is considered a vital process for CO₂ emission and conversion. Herein, we disclosed the integral role of the electronegativity of M atoms in Ni-MO_x supported catalysts to producing CH₄ molecules, which the satisfactory catalytic performance stemmed from the regulated ability to capture CO₂ molecules and CO intermediates. More importantly, alongside the extensively studied descriptor of particle size, we uncovered a strong correlation between the electronegativity of M atom and CH₄ selectivity, in which the CO/CO₂ adsorption capacity upon the Ni/NiO_x/MO_x interfaces exhibited a volcanic trend based on the electronegativity of M atoms in MO_x supports. The screened Ni-Y₂O₃ composite catalysts demonstrated excellent CO₂ methanation performance, suggesting the powerful practicability of the electronegativity of M atoms in MO_x supports as a descriptor. These findings not only shed fundamental insight into the reaction pathway but also paved the way for the rational design of Ni-based catalysts based on the simple descriptor of electronegativity.