Chiral-induced spin polarization in amorphous cobalt Iron hydroxide: Synergistic density of states and d-band modulation for efficient bifunctional water electrolysis.

The chiral-induced spin selectivity effect provides a brand-new idea for breaking through the activity limit of electrocatalytic reactions, but there is still little exploration of how to achieve spin regulation in amorphous catalytic systems. In this work, chiral amorphous cobalt‑iron hydroxide catalysts were successfully constructed on nickel foam (NF) by chiral ligand-induced electrodeposition. The magnetic conductive atomic force microscopy result confirms that the L-chiral catalyst (L-CoFeOxHy/NF) has a spin polarization degree as high as 90%. Besides, the L-CoFeOxHy/NF exhibits significantly enhanced catalytic activity for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The hydrogen evolution overpotential is 97 mV at 10 mA cm-2, and the oxygen evolution overpotential is 363 mV at 100 mA cm-2, which is significantly better than that of the achiral catalyst (DL-CoFeOxHy/NF). Mechanism studies show that the chiral structure induces a highly spin-polarized electron flow through the chiral-induced spin selectivity (CISS) effect. For the HER, the spin-polarized electron transport shifts the rate-determining step from the Volmer to the Heyrovsky pathway. For the OER, it accelerates the spin-matching kinetics of triplet oxygen generation and effectively inhibits the formation of the byproduct H2O2. This study provides a new strategy based on spin regulation for the development of efficient non-precious metal electrocatalysts.