Modified fly ash, a waste material from the energy industry, as a catalyst for the CO2 reduction to methane

Highlights: • New catalysts using a ball-mill mechanical energy from fly ash were obtained. • A conversion of carbon dioxide to methane of 58% was obtained at 350 °C. • Two catalysts are regarded as highly promising for future perspectives. A novel approach was used as support for synthesis of fly ash derived catalyst from waste fly ashes from the energy sector was used as support in the preparation of Ni-catalysts for CO₂ methanation. The catalysts were characterized by XRD, H₂ -TPR, CO₂ -TPD and N₂ low-temperature nitrogen sorption. As a result of application of new approach using a ball-mill mechanical energy, carbon dioxide conversion to methane of 58% was obtained at 350 °C. The conversion long with economical aspects of catalyst preparation, including waste material reuse, leads to highly promising results. The results indicate that the catalyst for the methanation process can be easily obtained by the mechanical activation of waste from the energy sector. The chemical modification is more complicated and does not give significantly better results. This approach to waste transformation is innovative, ecological, and economical. It meets the assumptions of the circular economy concept and allows to reuse of waste materials.