High-Performance Electrochemical and Photoelectrochemical Water Splitting at Neutral pH by Ir Nanocluster-Anchored CoFe-Layered Double Hydroxide Nanosheets

Highly efficient electrocatalysts for the oxygen evolutionreaction(OER) in neutral electrolytes are indispensable for practical electrochemicaland photoelectrochemical water splitting technologies. However, thereis a lack of good, neutral OER electrocatalysts because of the poorstability when H+ accumulates during the OER and slow OERkinetics at neutral pH. Herein, we report Ir species nanocluster-anchored,Co/Fe-layered double hydroxide (LDH) nanostructures in which the crystallinenature of LDH-restrained corrosion associated with H+ andthe Ir species dramatically enhanced the OEC kinetics at neutral pH.The optimized OER electrocatalyst demonstrated a low overpotentialof 323 mV (at 10 mA cm(-2)) and a record low Tafelslope of 42.8 mV dec(-1). When it was integrated withan organic semiconductor-based photoanode, we obtained a photocurrentdensity of 15.2 mA cm(-2) at 1.23 V versus reversiblehydrogen in neutral electrolyte, which is the highest among all reportedphotoanodes to our knowledge.

Automated summary

Highly efficient electrocatalysts for the oxygen evolution reaction (OER) in neutral electrolytes are crucial for practical water splitting technologies. However, there is a lack of good neutral OER electrocatalysts due to poor stability and slow kinetics at neutral pH. In this study, Ir species nanocluster-anchored, Co/Fe-layered double hydroxide (LDH) nanostructures were developed, which showed enhanced OER kinetics at neutral pH. The optimized OER electrocatalyst demonstrated a low overpotential and high performance when integrated with an organic semiconductor-based photoanode.