Comparative study of carbon fiber structure on the electrocatalytic performance of ZIF-67

In this study, novel ZIF-67@carbon fiber composites were fabricated by a simple and facile approach. In order to explore the influence of carbon fiber structure on enhancing the electrocatalytic efficiency of the ZIF-67, different structural carbon fibers (hollow porous carbon fiber (PCF) and solid carbon fiber (SCF)) were used for preparing ZIF-67/carbon fiber catalysts. ZIF-67/carbon fiber composites were characterized via X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical methods. Thanks to excellent hollow structural characteristic of PCF, ZIF-67/PCF possesses more exposed active sites, smaller particle size of ZIF-67, better conductivity, electrochemical stability, more mass transport channels as well as superior electrocatalytic abilities than ZIF-67/SCF. Furthermore, ZIF-67/PCF(1:1) sample-modified glassy carbon electrode presents a linear range to nitrobenzene that is composed by two line segments, i.e. from 0.3 to 50 μM with a sensitivity of 454.7 μA mM^-1 and from 50 to 390 μM with a sensitivity of 132.0 μA mM^-1, and a low detection limit of 0.16 μM. It also exhibits a wide linear response to l-cysteine in the range of 5-160 μM and 160-1580 μM with a rapidly response within 1.0 s as well as high catalytic rate constant, good stability and anti-interference ability. Our work provides useful information for searching and choosing carbon materials with excellent structure benefit to electrochemical applications.