Electrodes and electrocatalysts for electrochemical hydrogen peroxide sensors: a review of design strategies

Abstract

H₂O₂ sensing is required in various biological and industrial applications, for which electrochemical sensing is a promising choice among various sensing technologies. Electrodes and electrocatalysts strongly influence the performance of electrochemical H₂O₂ sensors. Significant efforts have been devoted to electrode nanostructural designs and nanomaterial-based electrocatalysts. Here, we review the design strategies for electrodes and electrocatalysts used in electrochemical H₂O₂ sensors. We first summarize electrodes in different structures, including rotation disc electrodes, freestanding electrodes, all-in-one electrodes, and representative commercial H₂O₂ probes. Next, we discuss the design strategies used in recent studies to increase the number of active sites and intrinsic activities of electrocatalysts for H₂O₂ redox reactions, including nanoscale pore structuring, conductive supports, reducing the catalyst size, alloying, doping, and tuning the crystal facets. Finally, we provide our perspectives on the future research directions in creating nanoscale structures and nanomaterials to enable advanced electrochemical H₂O₂ sensors in practical applications.