Tunable copper based slag catalyst for energy vectors production

Abstract

Steel slag is known to contain various metal oxides and minerals that have the potential to function as green and sustainable catalysts for chemical reactions. Previous studies demonstrated that, albeit calcium aluminate is the major constituent, the presence of iron oxides enables the slag to function as photocatalyst for CO₂ reduction reaction (CO₂RR) to formic acid, and that doping with palladium improves these properties. In this new study, a novel and more versatile catalyst was prepared by functionalizing the slag with CuO nanostructures. The hybrid material (CuO-slag) was characterized by XRD, XPS, FESEM and SEM-EDX techniques, while electrochemical measurements certified its photocatalytic properties. Catalytic tests demonstrated that it is capable to convert CO₂ into formic acid in good yields (231 μmol gcat^-1 h^-1), but also to push reduction reaction up to methanol (81.5 μmol gcat^-1 h^-1) and ethanol (40 μmol gcat^-1 h^-1), the latter under photo-thermal conditions. Finally, to further extend the scope of the hybrid material, the hydrogen evolution reaction (HER) was also investigated.