Optimizing Ni−Fe−Ga alloys into Ni<sub>2</sub>FeGa for the Hydrogenation of CO<sub>2</sub> into Methanol
Thomas Erik Lyck Smitshuysen, Monia Runge Nielsen, Tim Pruessmann, Anna Zimina, Thomas L. Sheppard, Jan‐Dierk Grunwaldt, Ib Chorkendorff, Christian Danvad Damsgaard
Abstract
Abstract A screening study of the catalytic performance of ternary alloy nanoparticles containing nickel, iron and gallium supported on silica for methanol synthesis from CO 2 and H 2 was performed. Catalysts were prepared by incipient wetness impregnation and subsequently reduced in H 2 before catalytic testing. Ni 2 FeGa showed the best performance of the tested catalysts in terms of methanol yield. An optimization of the preparation was done to improve activity and selectivity, reaching a performance close to that of commercially available Cu/ZnO/Al 2 O 3 /MgO at low reaction temperatures and pressure. Extensive in situ characterisation using environmental TEM, in situ XRD and in situ EXAFS of the formation of the Ni 2 FeGa catalyst explains an optimal reduction temperature of 550 °C: warm enough that the three atomic species will form an alloy while cold enough to prevent the catalyst from sintering during the formation.