Dual Tuning of Composition and Nanostructure of Hierarchical Hollow Nanopolyhedra Assembled by NiCo-Layered Double Hydroxide Nanosheets for Efficient Electrocatalytic Oxygen Evolution

NiCo-layered double hydroxides (LDHs) have recently emerged as potential oxygen evolution reaction (OER) catalysts in alkaline solutions. However, their preferred active sites have been ill-defined until now. In this work, hierarchical hollow nanopolyhedra assembled by NiCo-LDH nanosheets with adjustable composition and nanostructure are prepared via a facile selftemplated strategy. DFT calculations indicate that Co3+ hollow sites are the preferred adsorption and active sites. The resultant hierarchical NiCo-LDH hollow nanopolyhedra realize superior OER activity by optimizing the composition of NiCo-LDH, which achieves a 10 mA cm(-2) current density at an overpotential of 314 mV. This work not only presents deeper insights into the intrinsic OER electrocatalytic activity for NiCo-LDH but also elucidates on the further optimization of the OER properties of other bimetallic electrocatalysts.