Boosting dual function material Ni-Na/Al2O3 in the CO2 adsorption and hydrogenation to CH4: Joint presence of Na/Ca and Ru incorporation

Abstract

ICCU-methanation is a promising technology that would approach a carbon neutral cycle. In this paper, the feasibility of boosting the activity of the dual function material (DFM) 10Ni-16Na/Al2O3 through the joint presence of Na/Ca and the Ru incorporation is studied. Four DFMs are prepared by sequential wetness impregnation and are extensively characterized by N2 adsorption/desorption, XRD, H2 chemisorption, TEM, STEM-HAADF and temperature-programmed techniques (H2-TPD, CO2-TPD, TPSR, and H2-TPR). The catalytic behaviour of DFMs in the cyclic process of CO2 adsorption and hydrogenation to CH4 is evaluated. The joint presence of Na/Ca improves CH4 production at intermediate-high temperatures by boosting the CO2 adsorption capacity. On the other hand, the Ru incorporation promotes CH4 production at low-intermediate temperatures by presenting synergistic aspects with nickel that lead to a greater number of exposed metal atoms. The Ru incorporation increases the metallic dispersion and the Ni reduction. Finally, the joint presence of Na/Ca and the simultaneous Ru incorporation presents the best activity results. It is concluded that both positive effects are added. Specifically, the DFM 1Ru10Ni-NaCa produces 298 μmol g−1 at 440 °C with a CH4 selectivity of 98.4 %. Furthermore, it is also the most active and selective DFM after hydrothermal aging in the presence of O2.