Spin polarized oxygen evolution reaction in chiral amorphous manganese-doped cobalt oxide: Enhancing electrocatalytic activity via lattice oxygen participation

Abstract

Chiral-induced spin selectivity (CISS) in chiral inorganic materials has emerged as a promising strategy for enhancing water electrolysis by generating spin-polarized hydroxyl radicals with parallel spins, which favor the formation of triplet-state oxygen (oxygen evolution reaction, OER) while suppressing undesired, randomly oriented byproducts (H2O2). Here, we report that manganese doping into chiral amorphous cobalt oxides (Mn:CoOx) enhances oxygen evolution reaction (OER) performance by activating lattice oxygen reaction pathway while preserving the intrinsic CISS effects. Through in situ Raman spectroscopy, differential electrochemical mass spectroscopy (DEMS) and pH-dependent electrochemical characterization, we demonstrate that Mn doping induces a mechanistic transition from the conventional adsorbate evolution mechanism (AEM) to a lattice oxygen mechanism (LOM). Moreover, we confirm that Mn doping retains the spin-selective behavior of the chiral CoOx matrix, as evidenced by its continued suppression of H2O2 formation and enhanced OER performance. As a result, the optimized chiral Mn:CoOx electrocatalyst achieves a notably reduced overpotential of 266 mV at 10 mA cm-2 (208 mV with 90% iR compensation) compared 327 mV for undoped chiral CoOx. Moreover, chiral Mn:CoOx electrocatalyst achieves a current density of 11.14 mA cm-2 at 2.0 V, maintaining stable operation at 1 A cm-2 for over 1,000 hours in an anion exchange membrane water electrolyzer (AEMWE) single cell, highlighting its strong potential for spin-selective green hydrogen production under industrially relevant conditions.