Compressively strained Triple-layer IrO6/MnO6 Octahedral Nanosheets for Oxygen Evolution in Acid Media

Oxygen electrochemistry plays a key role in renewable energy technologies such as fuel cells and electrolyzers, but its slow kinetics limits the performance and commercialization of such devices. Here, a novel triple-layer IrO 6 /MnO 6 nanosheet was developed by a simple hydrothermal method. During the substitution of Mn by Ir, lattice compressive strain is introduced into the IrO 6 /MnO 6 nanosheets, thereby tuning their electronic structure to suit the favorite oxygen evolution reaction (OER) activity. This compressively strained nanosheet catalyst exhibits an excellent mass activity of 7882 A g − 1 at an overpotential of 270 mV in 0.5 M H 2 SO 4 , and reaches 10, 50 and 100 mA cm − 2 at overpotentials of only 62 mV, 197 mV and 234 mV, respectively, ranking the highest OER activity among the state-of-the-art values in acid media. The catalyst exhibits a remarkable stability even at 300 mA cm − 2 in 0.5 M H 2 SO 4 . Using the nanosheets as OER catalyst and NiMo alloy as hydrogen evolution reaction catalyst, a two-electrode electrolyzer achieves 10 mA cm − 2 with only a cell voltage of 1.46 V for overall water splitting in 0.5 M H 2 SO 4 . This strategy enables the material with high feasibility for practical applications on hydrogen production.