Polarization-induced efficient charge separation in an electromagnetic coupling MOF for enhancing CO2 photocatalytic reduction

Rapid recombination of photogenerated carriers severely impairs the performance of photocatalysts , while polarization is an effective driving force for increasing the charge separation and hence improving the photocatalytic activity . In this work, a series of magnetoelectric-coupled layered metal–organic framework (MOF) catalysts with different Co-doped contents (denoted as Ni-MOF and Co x Ni 1-x -MOF) are fabricated with different polarities and employed as novel photocatalysts for CO 2 photocatalytic reduction reaction. Our experiments show that the highest charge separation efficiency occurs in the Co 0.1 Ni 0.9 -MOF sample which has a maximal polarization. This Co 0.1 Ni 0.9 -MOF material has a best CO 2 reduction performance of 38.74 μmol g −1 h −1 which is at a high level in the currently reported layered materials. Meanwhile, it is found that a series of Co x Ni 1-x -MOF samples all display selectivity close to 100% for CO 2 reduction to CO, which is desirable for industrial applications. Theoretical analysis shows that Co doping alters the degree of distortion of the asymmetrical Ni-centered octahedron {NiN 2 O 4 } in Ni-MOF by replacing Ni due to the magnetoelectric coupling effect and Jahn-Teller effect, which results in adjustable polarity of Co x Ni 1-x -MOF. This work provides new insights on how to improve photogenerated charge separation in MOF by enhancing polarization.