Magnetically-enhanced water electrolysis for low-cost Hydrogen production (Hy-walHy) – Hy-walHy

The Hy-walHy project proposes to develop magnetically-enhanced alkaline water electrolyzers (AWE), on which LEPMI and LPCNO have recently established a proof-of-concept. The magnetic enhancement is due to the local transformation of a high-frequency alternating magnetic field (AMF) into heat using magnetic nanoparticles (Hyperthermia). To that goal, LPCNO developed a novel magnetically-responsive catalyst consisting of 15 nm nickel-coated iron carbide nanoparticles (FeC@Ni). The iron carbide magnetic core (crystalline Fe2.2C, noted “FeC”) displayed extremely large heating power and allowed the nanoparticles to heat when exposed to the AMF; the nickel shell was the catalytic phase able to electrochemically split water. LEPMI designed cells to perform electrochemical measurements under AMF and demonstrated that magnetic heating dramatically enhances the activity of the FeC@Ni catalyst for AWE, i.e. for the oxygen and hydrogen evolution reactions in 1 mol L-1 KOH. Under similar conditions, no activation has been recorded without magnetically-sensitive (FeC@Ni) nanoparticles.

Practically speaking, using the electrochemical three-electrode flow-cell developed in LEPMI, the OER overpotential during galvanostatic measurements could be decreased by up to 200 mV in a 40 mT electromagnetic field, in a range of current density from 10 to 25 mA cm-2. Furthermore, the hydrogen evolution reaction (HER) could also be activated by AMF, but in this case only at “high” current density up to 25 mA cm-2, for which the overpotential decreased by up to 75 mV in a 48 mT electromagnetic field.

To pursue this effort, the project will be organized according to two approaches: nano-engineering and multiphysics engineering, to tackle the technological issues associated to the innovative concept. On the (nano)materials’ side, large-heating-power nanoparticles, that exhibit good durability in operation and generate low reaction overvoltage, will be developed; on the engineering side, efforts will be focused on the design of electrochemical cells and inductors that are compatible with one-another and adapted to minimize the amount of energy required to generate the magnetic field, and enhance the overall process efficiency. The objective of the Hy-walHy project is to reach high current density (ca. 1 A cm-2) at low cell overvoltage (below 500 mV), using non-PGM catalysts, which remains beyond reach for state-of-the-art proton exchange membrane water electrolyzers.