Spin-polarization strategy for enhanced acidic oxygen evolution activity.

Spin-polarization is known as a promising way to promote anodic oxygen evolution reaction (OER) since the intermediates and products endow the spin-dependent behaviours, yet it rarely reported for ferromagnetic catalysts towards acidic OER practically used in industry. Herein, we report the first spin polarization mediated strategy to create a net ferromagnetic moment in antiferromagnetic RuO 2 via dilute manganese (Mn 2+ ) (S = 5/2) doping for enhancing OER activity in acidic electrolyte. Element selective X-ray magnetic circular dichroism reveals the ferromagnetic coupling between Mn and Ru ions, fulfilling the Goodenough-Kanamori rule. The ferromagnetism behaviour at room temperature can be well interpreted by first principles calculations as the interaction between Mn 2+ impurity and Ru ions. Indeed, Mn-RuO 2 nanoflakes exhibit a strongly magnetic field enhanced OER activity, with the lowest overpotential of 143 mV at 10 mA cm geo -2 and negligible activity decay in 480 hours stability (versus 200 mV/195 hours without magnetic field) as known for magnetic effects in literatures. The intrinsic turnover frequency is also improved to reach 5.5 s -1 at 1.45 V RHE . This work highlights an important avenue of spin-engineering strategy for designing efficient acidic oxygen evolution catalysts. This article is protected by copyright. All rights reserved.