High-Performance Nanoporous Carbon Derived from Zeolitic Imidazolate Framework-8: Influence of Ultrasonic Spray...

Nanoporous carbon (NPC) particles have attracted significant attention as promising supercapacitor electrode materials owing to their large surface area and tunable pore structure. In this study, we synthesized NPC particles via ultrasonic spray pyrolysis using Zeolitic Imidazolate Framework-8 (ZIF-8) as a precursor and investigated the effects of experimental parameters, including precursor concentration, carrier gas flow rate, and post-treatment, on the structure, morphology, and electrochemical properties of NPC particles. Increasing the precursor concentration led to larger particle sizes. Higher carrier gas flow rates generally resulted in slightly larger particles and greater residual Zn contents because the shorter residence time limited Zn volatilization during pyrolysis. HCl post-treatment effectively removed residual Zn and enhanced the specific surface area of NPC particles. The optimized sample synthesized at a precursor concentration of 0.21 wt % and a carrier gas flow rate of 0.4 L/min exhibited superior supercapacitor performance, delivering a high specific capacitance of 168.4 F/g at a current density of 1.0 A/g, along with good cycling stability, retaining 93.6% of its initial capacitance after 10,000 cycles at a current density of 10 A/g. These results demonstrate a simple and effective strategy for synthesizing high-performance NPC materials and provide valuable insights into the relationship between the processing parameters, structural properties, and electrochemical performance of advanced supercapacitor applications.