Thermal decomposition synthesis of Sr- modified ZnS quantum dots for hydrogen peroxide electrochemical sensing

Abstract

Hydrogen peroxide (H₂O₂) plays a critical role in various biological, environmental, and industrial processes, yet its excessive accumulation poses significant health and ecological risks. This study presents the synthesis of Sr-modified ZnS quantum dots (Sr@ZnS QDs) via a thermal decomposition method and their application as an innovative sensing material for the electrochemical detection of H₂O₂. The synthesized Sr@ZnS QDs exhibit nanoscale uniformity, high crystallinity, and abundant catalytic active sites, making them ideal candidates for sensor applications. The Sr@ZnS QDs were integrated into screen-printed carbon electrodes, resulting in sensors with exceptional performance. Electrochemical analyses, including cyclic voltammetry, differential pulse voltammetry and chronoamperometry, demonstrated a broad linear detection range (1–80 mM), high sensitivity (12.68 μA·mM⁻¹·cm⁻²), and a low detection limit (75.9 μM) at neutral pH. The Sr@ZnS QDs sensor showed excellent selectivity, effectively discriminating H₂O₂ from common interfering species such as NaCl, glucose, and hexane. Furthermore, the proposed catalytic mechanism revealed that the interaction of Sr²⁺ and Zn²⁺ ions with H₂O₂ plays a pivotal role in enhancing the redox reactions. This work introduces Sr@ZnS QDs as a promising material for the development of cost-effective, portable, and high-performance electrochemical sensors. The findings not only advance the field of H₂O₂ sensing but also open new possibilities for the broader application of Sr@ZnS QDs in environmental monitoring, clinical diagnostics, and industrial process control.