High-efficient water splitting over an in-situ growth novel electrocatalyst of metal-organic framework-based nanostructures.

Metal-organic frameworks (MOFs) as emerging material have drawn much attention to apply to the field of water splitting. In this paper, layered NiFe-MIL-53 and nanoflower-like CoFe-MOF-74 were sequentially grown on nickel foam through two-step in-situ growth to construct a MOF-74/MIL-53 heterojunction. On this basis, we used the localized surface plasmon resonance (LSPR) effect of gold nanoparticles (Au NPs) to significantly improve the oxygen evolution reaction performance of MOF-74/MIL-53 heterojunction. Under illumation, the obtained Au-MOF-74/MIL-53 exhibits a lower overpotential of 218 mV, which is far superior to commercial catalyst. The reaction kinetics are significantly enhanced due to the lower charge transfer resistance and the higher electric double layer capacitance. We confirmed the existence of charge transfer between Au NPs and MOFs, and at the same time, the deposition of Au NPs significantly reduced the charge transfer resistance of MOF-74/MIL-53. On the basis of our work, we provide a novel MOF-based electrocatalytic nanocomposite structure for efficient water splitting. • MOF-74/MIL-53 heterojunction is synthesized by in-situ growth method. • Nanoflower-like MOF-74, with more active centers, contributes to mass transfer. • Au-MOF-74/MIL-53 exhibits much lower overpotential than commercial catalysts. • MOF coupled with plasmonic Au NPs can effectively promote water splitting. [ABSTRACT FROM AUTHOR]