NiFe-layered double hydroxide arrays for oxygen evolution reaction in fresh water and seawater

The development of active, durable, and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is crucial for viable hydrogen production from water by electrolysis. In this work, we report a mild, atmospheric pressure-based chemical method for the synthesis of NiFe-containing layered double hydroxide (LDH) nanosheet arrays on a carbon fiber cloth (CC). The obtained NiFe-LDH/CC composites with various Ni/Fe ratios show good performance for OER in alkaline aqueous solutions. Among them, the sample with a Ni/Fe ratio of 6:4 exhibits the best OER activity with overpotential values of only 226 mV in water and 238 mV in seawater at a current density of 10 mA cm⁻², which are much lower than those of the benchmarking RuO₂ catalyst. The catalytic activity can be maintained for at least 450 h for OER in fresh water and 165 h in seawater at a current density of 100 mA cm⁻².