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

Abstract

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 oxygen evolution reaction (OER) process of CoFe-layered double hydroxide (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 a 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 and 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 hydrogen evolution reaction (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. Graphical abstract: [Figure not available: see fulltext.]