Cobalt Nanoparticles and Atomic Sites in Nitrogen‐Doped Carbon Frameworks for Highly Sensitive Sensing of Hydrogen Peroxide

Abstract In situ monitoring of hydrogen peroxide (H 2 O 2 ) during its production process is needed. Here, an electrochemical H 2 O 2 sensor with a wide linear current response range (concentration: 5 × 10 −8 to 5 × 10 −2 m ), a low detection limit (32.4 × 10 −9 m ), and a high sensitivity (568.47 µA m m −1 cm −2 ) is developed. The electrocatalyst of the sensor consists of cobalt nanoparticles and atomic Co‐N x moieties anchored on nitrogen doped carbon nanotube arrays (Co‐N/CNT), which is obtained through the pyrolysis of the sandwich‐like urea@ZIF‐67 complex. More cobalt nanoparticles and atomic Co‐N x as active sites are exposed during pyrolysis, contributing to higher electrocatalytic activity. Moreover, a portable screen‐printed electrode sensor is constructed and demonstrated for rapidly detecting (cost ≈40 s) H 2 O 2 produced in microbial fuel cells with only 50 µL solution. Both the synthesis strategy and sensor design can be applied to other energy and environmental fields.