A General Synthesis of Nanostructured Conductive Metal-Organic Frameworks from Insulating MOF Precursors for Supercapacitors and Chemiresistive Sensors

Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) are emerging as a unique subclass of layer-stacked crystalline coordination polymers that simultaneously possess porous and conductive properties, and have broad application potential in energy and electronic devices. However, to make the best use of the intrinsic electronic properties and structural features of 2D c-MOFs, the controlled synthesis of hierarchically nanostructured 2D c-MOFs with high crystallinity and customized morphologies is essential, which remains a great challenge. Herein, we present a template strategy to synthesize a library of 2D c-MOFs with controlled morphologies and dimensions via insulating MOFs-to-c-MOFs transformations. The resultant hierarchically nanostructured 2D c-MOFs feature intrinsic electrical conductivity and higher surface areas than the reported bulk-type 2D c-MOFs, which are beneficial for improved access to active sites and enhanced mass transport. As proof-of-concept applications, the hierarchically nanostructured 2D c-MOFs exhibit a superior performance for electrical properties related applications (hollow Cu-BHT nanocubes-based supercapacitor and Cu-HHB nanoflowers-based chemiresistive gas sensor), achieving over 225 % and 250 % improvement in specific capacity and response intensity over the corresponding bulk type c-MOFs, respectively. A template strategy has been developed for the general synthesis of hierarchically nanostructured 2D conjugated metal-organic frameworks (2D c-MOFs) with high crystallinity, tailored morphologies, and high porosity via insulating MOFs-to-c-MOFs transformations. These nanostructured 2D c-MOFs show great potential in supercapacitors and chemiresistive H2S sensors.+image

Automated summary

Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) are a subclass of layer-stacked crystalline coordination polymers that possess both porous and conductive properties, making them suitable for energy and electronic device applications. Controlled synthesis of hierarchically nanostructured 2D c-MOFs with customized morphologies and dimensions is essential to fully utilize their electronic properties and structural features. A template strategy has been developed to achieve this via insulating MOFs-to-c-MOFs transformations, resulting in higher surface areas and improved access to active sites. The hierarchically nanostructured 2D c-MOFs show superior performance in electrical properties related applications, such as supercapacitors and gas sensors, with significant improvements in specific capacity and response intensity compared to bulk-type c-MOFs.