Surface-neutralization engineered NiCo-LDH/phosphate hetero-sheets toward robust oxygen evolution reaction

Developing highly active oxygen evolution reaction (OER) electrocatalysts with robust durability is essential in producing high-purity hydrogen through water electrolysis. Layered double hydroxide (LDH) based catalysts have demonstrated efficient catalytic performance toward the relatively sluggish OER. By considering the promotion effect of phosphate (Pi) on proton transfer, herein, a facile phosphate acid (PA) surface-neutralization strategy is developed to in-situ construct NiCo-LDH/NiCoPi hetero-sheets toward OER catalysis. OER activity of NiCo-LDH is significantly boosted due to the proton promotion effect and the electronic modulation effect of NiCoPi. As a result, the facilely prepared NiCo-LDH/NiCoPi catalyst displays superior OER catalytic activity with a low overpotential of 300 mV to deliver 100 mA cm⁻² OER and a Tafel slope of 73 mV dec⁻¹. Furthermore, no visible activity decay is detected after a 200-h continuous OER operation. The present work, therefore, provides a promising strategy to exploit robust OER electrocatalysts for commercial water electrolysers.