Methanation of CO ₂ over Ni/clay: Effects of calcination temperature on catalyst properties and reaction intermediates formed

Abstract

Summary Ordinary clay is an abundant material and has the potential of being used as the low‐cost support of heterogenous catalysts. Thermal stability of ordinary clay is a question of concern for preparation of clay‐based catalyst for use at high temperature. In this study, Ni/clay catalyst with the clay calcined at varied temperature was prepared, characterized, and evaluated in the methanation of CO2. The results suggested that calcination at high temperature resulted in drastic sintering of clay, elimination of basic sites and further weakened the interaction of nickel with clay, leading to aggregation of nickel species. The in‐situ Diffused Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) study of methanation of CO2 indicated that the high calcination temperature of clay led to the abundant formation of undesirable specie such as CO32− which negatively affected the conversion of the reaction intermediates such as H2CO* to methane, resulting in the low catalytic activity. Highlights Ni weakly interacts with clay, leading to sintering in reduction/ methanation. High clay calcination temperature favors CO32‐ formation and slows down H2CO* conversion. Sintering of Ni rather than coking is major cause of catalyst deactivation.