Ultrasound-treated metal-organic framework with efficient electrocatalytic oxygen evolution activity.

Metal-organic frameworks (MOFs) and their derivatives are excellent candidates for electrocatalysts profiting from their unique structures and accessible active sites. Generally, due to the weak poor conductivity and catalytic activity when used as OER electrocatalysts, MOFs are more likely to be used as precursors to obtain composite catalysts through further pyrolysis treatment, rather than directly applied as OER electrocatalysts. But heat treatment usually results in structural collapse and loss of active sites. Specially, as a kind of two-dimensional (2D) materials with rapid electron transfer, metal-organic framework nanosheets (MONs) have great application potential in various fields, especially in the field of catalysis, due to the advantages of both MOFs and 2D materials. Here, we have reported a simple top-down approach to synthesize Co-MONs which can be directly adopted as efficient OER catalysts. Ultrasonic bath (40 KHz, 100 W) was employed to control the exposing of the preponderant lattice plane, which can offer plentiful active catalytic sites and accelerate ions transport. The optimized Co-MONs attain 10 mA cm-2 at an overpotential of 309 mV with a small Tafel slope of 75.71 mV dec-1.