Mono-coordinated metallocene ligands endow metal-organic frameworks with highly efficient oxygen evolution and urea electrolysis

Abstract

Metal-organic frameworks (MOFs) are generally recognized as promising platforms for energy conversion and storage due to their structural diversity and ligands tunability features, yet there are still challenges before practical applications become possible. Herein, a two-dimensional metal-organic framework (MOF) with mono-coordinated ferrocenecarboxylic acid (Fc) is successfully prepared. Different from the pure MOF, the as-prepared Fc-MOF offers remarkable electrocatalytic activity, exhibiting a low overpotential of 273 mV (vs. reversible hydrogen electrode) at 200 mA cm−2 and a small driving potential of 1.49 V (10 mA cm−2) for the overall water splitting with Pt/C as a counterpart cathode. The advance nature of the as-prepared Fc-MOF could also be evidenced by its remarkable Urea oxidation reaction (UOR) activity as it drives a current density of 10 mA cm−2 with a potential of 1.35 V. Theoretical calculations and experimental results demonstrate that the introduction of highly electronegative Fc not only change the electronic structure of MOF but also expose more unsaturated active sites, which in turn varies the adsorption features of the intermediate species during the catalytic process. This work represents a new pathway for exploration of highly efficient MOF based electrocatalysts.