Comparing thermoplastic electrode materials: Toward enhanced sensing of O2 and H2O2 in flow devices

Carbon composite electrodes often suffer from poor electrocatalytic activity and require complex, expensive, or time-consuming modifications to effectively detect certain analytes such as O₂ and H₂O₂. Thermoplastic electrodes (TPEs) are a new class of composite electrodes, fabricated by mixing commercial graphite with a thermopolymer, that exhibit superior electrochemical properties to typical carbon composite electrodes. This work investigates the properties of TPEs using two thermopolymer binders – polycaprolactone (PCL) and polystyrene (PS) – with sanded and heat-pressed surface treatments. XPS and SEM analysis suggested that sanded TPEs have a higher density of graphitic edge planes and improved electrochemistry as a result. Electrochemical detection of O₂ and H₂O₂ was demonstrated on sanded PS TPEs. Additionally, this work introduces the first use of a 3D-printed TPE template as part of a 3D-printed sensor module that is reversibly sealed with magnets as a proof-of-concept flow-based sensor for detecting H₂O₂.