Optimizing Water Oxidation Kinetics by Modulating Spin Alignment through Non-metal Vacancy Engineering

The efficiency of water splitting is primarily hampered by the sluggish kinetics of the oxygen evolution reaction (OER). Recently, increasing attention has been drawn to leverage spin polarization under an external magnetic field. However, the application of a magnetic field requires additional energy consumption and poses design challenges. Herein, we propose a simple defect engineering strategy aimed at aligning spins in paramagnetic materials to achieve an enhanced intrinsic OER activity. The hydrogenated NiFeP with P vacancies demonstrates elevated saturation magnetization (M_S) and reduced overpotential (M_S = 5.8 emu/mg, η₁₀ = 303 mV) compared to the untreated NiFeP sample (M_S = 1.2 emu/mg, η₁₀ = 341 mV). We elucidate the underlying mechanism of the spin magnetic effect on the OER performance and provide insights into the intricate relationship among vacancies, saturation magnetization, spin state alignment, and oxygenated intermediates. These insights contribute to a better understanding and design of catalysts at the spintronic level, paving the way for more efficient water splitting processes.