Improved water electrolysis using magnetic heating of FeC–Ni core–shell nanoparticles
Christiane Niether1,2, Ste?phane Faure3, Alexis Bordet3, Jonathan Deseure1,2, Marian Chatenet 1,2,4*, Julian Carrey3*, Bruno Chaudret3 and Alain Rouet5
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 nanoparti- cles, 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 evolu- tion 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.