In situ etch engineering of Ru doped NiFe(OH)x/NiFe-MOF nanocomposites for boosting the oxygen evolution reaction

Metal-organic frameworks (MOFs) have been deemed as promising electrocatalysts for electrochemical water oxidation; however, the poor electronic conductivity and stability are still intractable issues hindering their practical applications. Herein, an efficient in situ etching strategy is employed to transform part of the pristine NiFe-MOF into active NiFe(OH)(x) and simultaneously induce the exposure of abundant defective areas, which not only facilitates the electron transfer efficiency for the oxygen evolution reaction (OER), but also enables the accessibility to further anchor Ru. Benefiting from the synergistic contributions of Ru, NiFe(OH)(x) and NiFe-MOF, the as-fabricated Ru/NiFe(OH)(x)/NiFe-MOF nanocomposite exhibits an enhanced OER activity with a low overpotential of 242 mV at a current density of 10 mA cm(-2), and a two-electrode Ru/NiFe(OH)(x)/NiFe-MOF||Pt/C electrolyzer also requires a considerably low voltage of 1.54 V at 10 mA cm(-2) for overall water splitting. Moreover, taking both experimental and mechanistic results into account, the introduction of a small amount of Ru is able to induce a stronger adsorption between electrochemically active sites and oxygen-related intermediates, thus facilitating the OER activity.

Automated summary

An efficient in situ etching strategy is employed to transform part of the pristine NiFe-MOF into active NiFe(OH)(x) and simultaneously induce the exposure of abundant defective areas, which not only facilitates the electron transfer efficiency for the oxygen evolution reaction (OER), but also enables the accessibility to further anchor Ru, leading to enhanced OER activity.