Magnetic proximity-induced spin injection suppresses singlet oxygen for durable water electrolysis

Abstract

While spin polarization accelerates the oxygen evolution reaction (OER) kinetics, the parasitic generation of singlet oxygen (1O2) triggers oxidative degradation of catalytic active sites, limiting the lifespan of water electrolysis. Herein, we design a 1D directionally ordered CoFeB/CoFe-LDH (CFB/LDH) heterostructure to realize spin-injection via the magnetic proximity effect (MPE). Through exchange coupling, the ferromagnetic CFB core breaks the local spin symmetry of the ultrathin LDH shell. Under a magnetic field (MF), this MPE-induced spin alignment dynamically steers the OER toward the lattice oxygen mechanism. By enforcing spin conservation, the parallel-aligned heterostructure promotes effective interfacial spin filtering, which suppresses the 1O2 pathway by 6% h−1 in favor of ground-state triplet oxygen. Consequently, the MPE-driven catalyst achieves a 36 mV reduction in OER overpotential. When integrated into a practical anion-exchange membrane water electrolyzer, it delivers a cell voltage of 1.78 V at 500 mA cm−2, representing a 40 mV reduction compared to the cell without MF, and sustains stable operation for 200 h with a negligible potential increase. This work establishes MPE-induced spin injection as a materials-design strategy for coupling interfacial spin polarization with durable and efficient water electrolysis.