A General Synthesis of Nanostructured Conductive MOFs from Insulating MOF Precursors for Supercapacitors and Chemiresistive Sensors

Two‐dimensional conjugated metal‐organic frameworks (2D c‐MOFs) are emerging as unique layer‐stacked crystalline coordination polymers that simultaneously possess porous and conductive properties. However, the controlled synthesis of hierarchically nanostructured 2D c‐MOFs with high crystallinity and customized morphologies is essential for energy and electronic devices, which remains a great challenge. Herein, we present a template strategy to synthesize 12 different 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 (up to 102 S cm‐1) and higher surface areas (up to ~62 times) 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 resultant hollow Cu‐BHT nanocube‐based supercapacitor exhibits over 2.3‐fold improvement in specific capacity (364.5 F g‐1) in organic electrolyte than the bulk‐type Cu‐BHT (161.9 F g‐1), surpassing the reported MOF‐based electrodes (up to 202 F g‐1). In addition, the Cu‐HHB nanoflower‐based chemiresistive gas sensor displays over 2.5‐fold enhancement in response intensity toward H2S compared to bulk‐type Cu‐HHB, boasting the fastest response speed and one of the lowest limits of detection ever reported for H2S sensors at room temperature.