Water electrolysis enables the storage of renewable electricity via the chemical bonds of hydrogen. However, proton-exchange-membrane electrolysers are impeded by the high cost and low availability of their noble-metal electrocatalysts, whereas alkaline electrolysers operate at a low power density. Here, we demonstrate that electrocatalytic reactions relevant for water splitting can be improved by employing magnetic heating of noble-metal-free catalysts. Using nickel-coated iron carbide nanoparticles, which are prone to magnetic heating under high-frequency alternating magnetic fields, the overpotential (at 20 mA cm⁻²) required for oxygen evolution in an alkaline water-electrolysis flow-cell was decreased by 200 mV and that for hydrogen evolution was decreased by 100 mV. This enhancement of oxygen-evolution kinetics is equivalent to a rise of the cell temperature to ~200 °C, but in practice it increased by 5 °C only. This work suggests that, in the future, water splitting near the equilibrium voltage could be possible at room temperature, which is currently beyond reach in the classic approach to water electrolysis.

水电解能够通过氢的化学键存储可再生电力。然而，质子交换膜电解槽因其贵金属电催化剂的高成本和低可用性而受到阻碍，而碱性电解槽以低功率密度运行。在这里，我们证明与水分解有关的电催化反应可以通过采用无贵金属催化剂的磁性加热来改善。使用容易在高频交变磁场下磁加热的镀镍碳化铁纳米颗粒，其超电势（在20 mA cm ^-2时））使碱性水电解流通池中的氧气释放所需的）降低了200 mV，而析氢所需的氧气减少了100 mV。氧气释放动力学的这种增强等同于将电池温度升高至〜200°C，但实际上仅增加了5°C。这项工作表明，将来在室温下可能会在平衡电压附近分裂水，这在经典的水电解方法中目前是无法实现的。