Facet engineering in metal organic frameworks to improve their electrochemical activity for water oxidation.

The facet effect has been well demonstrated for nanocrystal catalysis, however it is rarely revealed in metal organic frameworks (MOFs). Herein, we present a facile way to construct 2D zeolitic imidazolate framework-67 (ZIF-67) with dominant exposure of the (002) facets. We discovered that the ZIF-67 (002) facet exhibited the highest catalytic activity for oxygen evolution reaction (OER) among the (002), (011), and (111) facets. Moreover, this facet engineering is also available for ZIF-8 nanocrystals.