Co2+ ion-doped MnO2 electrode for microfluidic H2O2biosensors: formation, characterization, and catalytic performance

Abstract

H₂O₂ serves as a vital signalling molecule within biological systems and presents potential as a disease biomarker.Consequently, the development of sensitive and accurate sensors for its measurement within microfluidic systems is of significant importance. This article focuses on the development of a working electrode for an electrochemical microfluidic system designed for the quantitative determination of hydrogen peroxide. Here, we show that a MnO₂-based catalytic material can be improved by adding Co²⁺ ions. By changing the Co²⁺ concentration, an electrode material with improved catalytic performance was formed. The results of amperometric measurements of catalytic activity show a substantial increase in sensitivity and an expanded range of H2O2 concentrations that can be quantified using the new electrode. The characteristics of the Co²⁺-modified MnO₂ electrode were thoroughly examined by SEM, XPS. The combination of previously accumulated material and new data offers insights into the underlying reasons for the high catalytic activity of MnO2, supported by quantum-chemical calculations. This research lays the groundwork for a method utilizing utilising MnO₂ as a working electrode for detecting the concentration of H₂O₂ within a microfluidic cell. During experiments, a stop-flow protocol is employed, enabling data collection from coulometric measurements of the electrochemical processes occurring on the electrode within a limited measurement timeframe.