Morphology regulation of metal-organic framework-derived nanostructures for efficient oxygen evolution electrocatalysis

Understanding the relationship between the morphology of the metal-organic framework-derived nanostructures and their performance as catalysts in the oxygen evolution reaction (OER) is very important and highly desirable, because such a study would provide a new insight into the systematic regulation of the catalyst morphology for performance enhancement in electrocatalysis and photocatalysis. Here, a series of accurately morphology-regulated electrocatalysts (including nanosheets, nanoflowers, nanotubes and aggregations) derived from Hofmann-type metal-organic frameworks (MOFs) are reported for efficient OER. Among all the nanostructures, FeNi nanosheets show the best OER catalytic performance in alkaline media, achieving a low overpotential of 248 mV at 10 mA cm⁻², an ultra-small Tafel slope of 31.2 mV dec⁻¹and a satisfactory stability, greatly outperforming the commercial RuO₂ catalyst. The reason is that FeNi nanosheets possess optimized conductivity, oxygen vacancies and N-related active sites. Our research also demonstrates that electron transfer can be achieved through the precise control of the morphology of precursor MOFs.