Operando Electro-Oxidation Reconstitution of a Newly Designed 2D Co(II)-MOF on Nickel Foam to Cobalt Oxyhydroxide Nanosheets towards Energy Sustainability: A Holy Grail in Electrocatalytic Water Splitting.

The upsurging of cost-effective electrocatalysts through the operando electro-oxidation approaches holds great promise for the scalable production of green energy in the pursuit of energy sustainability. This work introduces an operando electro-oxidation reconstitution strategy in producing a smart electrocatalyst, cobalt "oxyhydroxide" derived from a newly designed 2D cobalt(II) metal-organic framework (-) directly grown on nickel foam (NF), . The electrocatalyst, , exhibits an outstanding overpotential of 76 mV for the hydrogen evolution reaction and 336 mV for the oxygen evolution reaction to achieve a current density of 10 mA/cm with remarkable Faradaic efficiencies of 97.1 and 93.4%, respectively, in 1 M aqueous KOH. Unveiling the bifunctionality of as the cathode and anode for overall water splitting in 1 M aqueous KOH, a low voltage of 1.65 V was needed to obtain 10 mA/cm current density. Nonetheless, displayed excellent stability for 12 h as evidenced from the chronopotentiometry recorded at 10 mA/cm. The outstanding bifunctional electrocatalytic performance and stability of the electrocatalyst for 50 h is attributed to the unique 2D hexagonal nanosheet morphology of and the microporous structure with zigzag flow channels of NF, facilitating a faster kinetics through the Co and Ni dual sites synergism.