Manipulating spin polarization by in-situ reconstructed amorphous/crystalline CoFe-LDH for efficient electrocatalytic water splitting

The performance of oxygen electrocatalysis is dependent on spin-related electron transfer behavior and orbital interactions. Herein, we report a simple spin-polarized approach to enhance the OER process of CoFe-LDH. The amorphous/crystalline CoFe-LDH nanosheets (a/c-CoFe-LDH) are prepared via acid-etching assisted co-precipitation to construct abundant amorphous/crystalline interfaces. The a/c-CoFe-LDH with controlled amorphous degree leads to manipulable magnetism, thus altering symmetric distribution of the d-orbital spin-electron states and facilitating spin-selective electron transfer process. The adsorbed O species will predominantly settle on a fixed spin direction, which propels the production of triplet oxygen. As the result, the amorphous/crystalline heterostructure contributes to suitable d-band centers, thus optimizing the adsorption strengths of oxygen-generated intermediates. Besides, the unsaturated coordination metals induce the generation of oxygen non-bonding states thus prompting oxygen as the redox center, thus triggering the lattice oxidation mechanism (LOM). Meanwhile, the crystalline structure endows excellent intrinsic conductivity and persistent stability. The obtained a/c-CoFe-LDH achieves low overpotentials of 269 mV at 10 mA cm^-2 in 1.0 M KOH towards the OER. To further enhance HER performance, Pt nanocluster was introduced into a/c-CoFe-LDH. This study offers a controllable method to prepare amorphous/crystalline electrocatalysts with regulated spin configuration for efficient water splitting.