Manganese-promoted Ni/Al2O3 catalysts for effective CO2 methanation

Hydrogenation of CO 2 to methane is a feasible solution to the growing global environmental and energy challenges. Nickel-based catalysts are efficient and cost effective for CO 2 methanation. Hernin, we synthesized Mn-promoted Ni/Al 2 O 3 catalysts with facilitated CO 2 methanation and elucidated the crucial role of Mn. After Mn doping, NiMn/Al 2 O 3 catalysts showed improved NiO dispersion. Subsequently, H 2 reduction and CO 2 methanation treatments resulted in reduction of NiO and MnO 2 into Ni and MnO, and incorporation of Ni 2+ into MnO lattice, forming NiMnO x and creating numerous Ni-NiMnO x interfaces. The abundant oxygen vacancies from NiMnO x could enhance CO 2 activation. Moreover, oxygen vacancies at the interface also promote electron transfer from Ni and MnO, leading to electron-poor Ni nanoparticles and thus significantly promoting the *CO methanation. Ultimately, the electron-poor Ni nanoparticles and abundant oxygen vacancies at the Ni-NiMnO x interface jointly facilitate CO 2 methanation.