Hierarchically porous carbon nanofibers embedded with cobalt nanoparticles for efficient H2O2 detection on multiple sensor platforms

Abstract

Hydrogen peroxide (H2O2) detection is essential in many industrial and biological processes. Current applications of H2O2 electrochemical sensors are often limited by the high cost of precious metal electrocatalysts and sophisticated instrumentation requirements. Here, we demonstrate a highly active non-precious metal cobalt/carbon nanocomposite electrocatalyst for efficient H2O2 sensing on multiple sensor platforms, including conventional glassy carbon electrodes (GCEs), free-standing film electrodes, and screen-printed electrodes (SPEs). This nanocomposite was synthesized by carbonation of electrospun polyacrylonitrile nanofibers containing zeolitic imidazole framework (i.e., ZIF-67) particles. The resulting hierarchically porous nitrogen-doped carbon nanofiber film contains hollow mesoporous carbon particles and exposed cobalt nanoparticles, which has sufficient mechanical strength as a self-standing film and is also electrically highly conductive. Consequently, when tested using GCEs, it exhibits an ultrahigh sensitivity of 300 μA/cm2 mM and a detection limit of 10 μM below the permissible H2O2 residual limit in food packaging permittable by the US FDA. When utilized as free-standing film electrodes, its linear detection range extends an order higher to 50 mM. It is also highly specific toward H2O2 sensing without responses to multiple interfering analytes. Further, it enables mobile H2O2 detection on SPEs when integrated with a portable potentiostat and mobile phone. This new nanocomposite electrocatalyst can open various new opportunities for practical H2O2 sensing applications.