Advanced hydrogen peroxide sensor based on modified platinum nanoparticles through square wave voltammetry

Morphological and size control of Pt nanoparticles (PtNPs) has long been pursued to improve the catalytic performance of Pt-based electrochemical sensors during recent decades. In this study, a high‑performance hydrogen peroxide sensor was developed by electrochemically depositing PtNPs onto a polyaniline‑modified glassy carbon electrode (PANI/GCE). Subsequently, the PtNPs/PANI/GCE electrode was separately subjected to two distinct methods, namely square wave (SW) treatment and square wave voltammetry (SWV). It was found that SWV was able to alter the exposed surface of platinum nanoparticles from (111) to (200), which leads to the formation of the angular nano-edges on the original Pt nanospheres. This structural transformation effectively increased the number of active sites and enlarged the effective surface area for the catalytic redox reaction of hydrogen peroxide. Owing to such advantages, the prepared PtNPs/PANI/GCE-SWV electrode exhibits a wide linear range from 50 μM to 30 mM and an excellent sensitivity of 294.90 μA·mM⁻¹·cm⁻² for H₂O₂ detection. In addition, SWV endowed the fabricated sensor with superior stability and reproducibility, thereby demonstrating promising prospects in the commercialization of stretchable and wearable biosensors.