Electrochemical Construction of Low-Crystalline CoOOH Nanosheets with Short-Range Ordered Grains to Improve Oxygen Evolution Activity

In this study, low-crystalline CoOOH nanosheet arrays that are grown on carbon fiber cloth (LC-CoOOH NAs/CFC) were prepared using a facile electrochemical strategy for the oxygen evolution reaction (OER). The low-crystalline CoOOH nanosheets were assembled randomly by numerous short-range (1–5 nm) ordered grains with different orientations, inducing abundant grain boundaries (edge sites of CoOOH). Moreover, a certain number of structural defects (oxygen vacancies) were also engineered on the low-crystalline CoOOH nanosheets. Benefiting from these abundant edge sites of CoOOH and oxygen vacancies, LC-CoOOH NAs/CFC exhibit much improved OER activity compared to the high-crystallinity CoOOH NAs/CFC with a perfect structure. This research provides a new way to synthesize the defective materials with a short-range ordered structure and lays a valuable theoretical foundation for the structure and property of OER catalysts.