ZIF-67 derived cobalt-based nanomaterials for electrocatalysis and nonenzymatic detection of glucose: Difference between the calcination atmosphere of nitrogen and air

Calcination of metal-organic frameworks (MOFs) with designed condition is an efficient and flexible method to synthesize electrocatalysts with high activity toward various applications. In this work, we propose a facile calcination procedure under N-2 atmosphere utilizing zeolitic imidazolate framework-67 (ZIF-67) as the precursor to obtain cobalt nanoparticles-porous carbon composites (denoted as ZIF-N-2) for nonenzymatic glucose detection in alkaline media. At the same time, calcination of ZIF-67 under air atmosphere with the same temperature was also carried out. The resulting product (denoted as ZIF-Air) was used as a comparison when evaluating the electrochemical performance of ZIF-N-2. By means of a series of physicochemical and electrochemical characterizations, different calcination atmosphere show great effect on the properties of the resulting materials. ZIF-N-2 shows the specific morphology with Co nanoparticles loaded on the porous carbon matrix, with superior conductivity, mass activity, and electrochemical effective surface area to ZIF-Air. Based on these distinct parameters, nearly 10 times higher response of ZIF-N-2 is obtained toward glucose than that of ZIF-Air. The sensitivity of ZIF-N-2 is calculated to be 0.227 mA mM(-1) cm(-2) in the linear range of 0.1-1.1 mM, with LOD of 5.69 mu M. Finally, the nonenzymatic glucose sensing performance of ZIF-N-2 modified screen-printed carbon electrode including selectivity, long-term stability and reproducibility were also proved to be outstanding. This work demonstrates the calcination of MOFs under designed condition can be a promising method to obtain electrocatalysts for electrochemical sensing application.