Enhanced oxygen evolution reaction via the tunability of spin and electronic states in a flexible van der Waals...

Perovskite transition metal oxide membranes with exact chemical composition and ordered lattice structures facilitate atomic-level catalytic mechanisms in diverse electrochemical processes, thus aiding in the development and design of potential catalysts. Nevertheless, the puzzling ascendancy of spin in the oxygen evolution reaction (OER) process remains an enigma owing to the robust correlation between TM 4d and oxygen 2p orbitals. Herein, we employed SrRuO3 (SRO) with 4d electron states as a ferromagnetic catalyst for the OER, which were deposited onto the flexible mica substrates. By applying compressive or tensile stresses to the SRO film, the bipolar enhancement of OER activity was observed. At the potential of 1.8 V, the current density (j) of SRO enhanced by ∼34% or ∼44%, with a 0.2% compressive or tensile strain, respectively, attributing to the diminished chemisorption of Ru-O. In addition, it was found that j enhanced by ∼86% or ∼104% and the overpotential reduced by ∼20% or ∼26% at a 0.2% compressive or tensile strain with a 13 kOe in-plane (IP) magnetic field, respectively. Those were attributing to the enhancement of the double exchange effect and the concentration of O22- in SRO, thus promoting electron transfer and regulating the adsorption/desorption capacity of reaction intermediates, respectively. Moreover, the magnetohydrodynamic-induced bubble effect is one of the factors that enhance the electrocatalytic activity. This investigation offers experimental evidence to comprehend the regulation of spin degree and electronic state during OER, hence advancing the design and engineering of the flexible magnetoelectrochemistry catalysts with encouraging prospects.