Detecting residual chemical disinfectant using an atomic Co–Nx–C anchored neuronal-like carbon catalyst modified amperometric sensor

Abstract

Hydrogen peroxide (H₂O₂) solution and its aerosols are common disinfectants, especially for urgent reuse of personal protective equipment during the COVID-19 pandemic. Highly sensitive and selective evaluation of the H₂O₂ concentration is key to customizing the sufficient disinfection process and avoiding disinfection overuse. Amperometric electrochemical detection is an effective means but poses challenges originated from the precarious state of H₂O₂. Here, an atomic Co–N_x–C site anchored neuronal-like carbon modified amperometric sensor (denoted as the CoSA-N/C@rGO sensor) is designed, which exhibits a broad detection range (from 250 nM to 50 mM), superior sensitivity (743.3 μA mM⁻¹ cm⁻², the best among carbon-based amperometric sensors), strong selectivity (no response to interferents), powerful reliability (only 2.86% decay for one week) and fast response (just 5 s) for residual H₂O₂ detection. We validated the accuracy and practicability of the CoSA-N/C@rGO sensor in the actual H₂O₂ disinfection process of personal protective equipment. Further characterization verifies that the electrocatalytic activity and selective reduction of H₂O₂ is determined by the atomically dispersed Co–N_x–C sites and the high oxygen content of CoSA-N/C@rGO, where the response time and reliability of H₂O₂ detection is determined by the neuronal-like structure with high nitrogen content. Our findings pave the way for developing a sensor with superior sensitivity, selectivity and stability, rendering promising applications such as medical care and environmental treatment.