Magnetic Field Enhancing OER Electrocatalysis of NiFe Layered Double Hydroxide

Electrocatalytic oxygen evolution reaction (OER) is widely used in the field of energy and chemical industry, such as metalair batteries and water splitting. Due to its unique layered structure and excellent stability, NiFe layered double hydroxide (LDH) is considered as one of the most promising electrocatalysts for OER in an alkaline environment. The further improvement of the OER performance of NiFe LDH still plagues its development. Herein, we directly applied the external magnetic field to improve the electrocatalytic activity of NiFe LDH toward OER. The overpotential of the NiFe LDH could achieve at only similar to 207 mV at a current density of 10 mA cm(-2) when the external magnetic field of 200 mT was applied. The Tafel slope of the NiFe LDH is also reduced to 41.7 mV dec(-1) under the action of a magnetic field of 200 mT. For the paramagnetic NiFe LDH, the OER magnetic field enhancing effect on the NiFe LDH probably mainly originated from the magnetohydrodynamic effect and charge transfer effect at the electrode/electrolyte interface induced by the magnetic field. The alignment of magnetic moments of NiFe LDH raised from the magnetization may also have a positive effect. [GRAPHICS] .

Automated summary

This study demonstrates the improved electrocatalytic activity of NiFe LDH towards OER by applying an external magnetic field. The results show a significant reduction in overpotential and Tafel slope of NiFe LDH under a magnetic field of 200 mT. The magnetic field enhancing effect is likely derived from magnetohydrodynamic effects, charge transfer effects, and alignment of magnetic moments of NiFe LDH.