Two-Dimensional Metal-Organic Framework Nanosheet Supported Noble Metal Nanocrystals for High-Efficiency Water Oxidation

It still remains a challenge to simultaneously optimize the nanostructure and electronic structure of electrocatalysts of noble-metal-based electrocatalysts to improve their performance and reduce their noble metal loadings, in which the dispersion and activity of the noble metal components play an important role. A series of hybrids of noble metal nanocrystals (NMNCs) and two-dimensional metal-organic framework (2D MOF) nanosheets are designed and synthesized by a facile, fast, and general approach, in which NMNC dispersion is quickly mixed with MOF precursors at room temperature. The NMNCs/2D MOF hybrids, denoted as M-Ni-NS (M = Ir, Ru or Pt, etc.), are assembled by taking advantage of abundant O-atom arrays on the surface the of 2D MOF nanosheets and they enable excellent dispersity and stability. Experimental and computational results show that the M-O-Ni bridging bonds realize successful tuning of the electronic structure of active sites and modify their activity. Taken together with the merits of the nanostructure of the 2D MOF support, this multiscale optimization strategy produces Ir-Ni-NS electrocatalysts with excellent performance for the oxygen evolution reaction, achieving a low overpotential of 270 mV at 10 mA cm(-2) in alkaline media and long time stability.