Magnetoelectrocatalysis: Evidence from the Hydrogen Evolution Reaction.

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-Fe 2 O 3 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 Fe 3 O 4 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.