Deeply Reconstructed NiFe Layered Double Hydroxide Nanosheets for an Efficient Oxygen Evolution Reaction

Layered double hydroxide (LDH) has shown great promise for oxygen evolution reaction (OER) in an alkaline solution, but its catalytic performance is still hindered by inadequate active sites and large overpotentials. Here, we report a robust solvothermal reconstruction strategy that can induce rich cavities and active sites in fluorinated NiFe LDH (NiFe-F) electrocatalysts for excellent OER activities. In the process of reconstruction, partial fluoride ions and metal cations (Fe3+) are leached from the catalyst in the alkaline solution at an elevated temperature. This leads to an effective bulk and surface reconstruction, drastically increasing the electrochemical active surface area and exposing more catalytic active sites, therefore improving the kinetics of the reaction and optimizing the binding energy of OER intermediates, as evidenced in our systematic electrochemistry studies and the density functional theory calculations. The reconstructed NiFe-F catalyst exhibits an unprecedented high activity toward OER among the non-noble metal catalysts, with a low overpotential (eta) of 152 mV at 10 mA cm-2, high turnover frequency of 1.6 x 10-1 s-1 at eta = 200 mV, and small activation energy of 12.8 kJ mol-1 at 1.23 VRHE, and excellent stability in the chronopotentiometry at 10 mA cm-2 for 100 h. This study offers a robust reconstruction strategy toward OER catalyst design for the next-generation clean energy conversion.