posted on 2024-01-03, 14:36authored byKrysti
L. Knoche Gupta, Heung Chan Lee, Johna Leddy
Hydrogen evolution reaction (HER) rates are higher where
magnetic
gradients are established at electrode surfaces. In comparison of
literature data for metals with comparable work functions, we note
1000× higher rates for paramagnetic metals than diamagnetic
metals. With unpaired electron spins, paramagnetic and ferromagnetic
metals establish interfacial magnetic gradients. At diamagnetic electrodes,
gradients are induced by addition of magnetized microparticles. Onset
of hydrogen evolution for magnetized γ-Fe2O3 microparticles in Nafion on diamagnetic glassy carbon electrodes
is lower by 190 mV (−18 kJ mol–1) relative
to demagnetized microparticles. Chemically the same as demagnetized
particles, the physical distinction of magnetic field and gradient
at magnetized microparticles increases electron transfer rate. For
magnetized Fe3O4 microparticles, the onset is
lower by 280 mV (−27 kJ mol–1). Paramagnetic
platinum electrodes are unaffected by addition of magnetized microparticles.
Magnetoelectrocatalysis is established by magnetic gradients.