A promising CO2 methanation catalyst system based on modified halloysites as supports

Abstract Earth’s climate is warming due to anthropogenic emissions of greenhouse gases, especially carbon dioxide (CO 2 ). Different reactions are allocated to mitigate the CO 2 in the atmosphere. However, CO 2 methanation is a pivotal research hotspot due to its ability to produce methane at low operating temperatures (200–400 °C). Halloysite nanotubes (HNTs)-based catalysts have attracted significant attention in various catalytic applications. However, Halloysite is rarely reported for thermal CO 2 methanation. The selected halloysite clay was modified first using the 3-Aminopropyl triethoxy silane (NH 2 ) as coupling agent, the resulting materials (HNTs), and then doped with Ni at different weight concentrations (5%, 10%, 20%, 40%, 50%). materials can offer high surface area and porous structure, which can improve metal dispersion. The prepared Ni/HNTs catalysts were characterized using various techniques, such as XRD, XPS, SEM, and TEM, which confirmed the existence of nanotubes and porous structures. The propensity of the prepared Ni/HNTs were evaluated to catalyse the CO 2 methanation reactions at a temperature range of 250 to 500 ̊C. The catalyst containing 20 wt.% of Ni (20Ni/HNTs) showed the highest CO 2 conversion at all reaction temperatures and the highest selectivity of methane at 450 °C (82%). This study paves the way for the large utilization of the HNTs as a strong support for different metals used in thermal catalytic reactions, not limited to the CO 2 methanation. Graphical Abstract