Breaking the scaling relations of oxygen evolution reaction on amorphous NiFeP nanostructures with enhanced activity for overall seawater splitting

The instinct scaling relations between the adsorption energies of key intermediates during OER lead to large overpotential for water/seawater splitting. Herein, we develop a new strategy to fabricate amorphous nickel-iron phosphides (NiFeP) with controllable morphologies as high-performance catalysts for overall seawater splitting. The ligand effect of P tunes the electronic states of the oxidized NiFe sites, thus breaks the scaling relations for OER and reduce the adsorption energy gap between HO* and HOO* from 3.08 eV to 2.62 eV. The NiFeP nanostructures exhibit extraordinarily low overpotentials of 129 mV for OER and 126 mV for HER at 100 mA cm-2 in simulated alkaline seawater, which outperform the best reported electrocatalysts. They could also be operated at 1.57 V with 100 mA cm-2 in a two-electrode electrolyzer and work for more than 500 h. Our work may provide a universal guidance for the design of highly active seawater splitting electrocatalysts.

Automated summary

By controlling the morphology of amorphous nickel-iron phosphides, we have successfully reduced the adsorption energy gap of key intermediates in the redox reactions, resulting in low overpotential electrocatalytic performance in simulated alkaline seawater.