Silica-based electrodes for electrochemical sensing of heavy metal ions - emerging trends and insights

Micropollutants, including heavy metal ions (HMIs), are emerging as a substantial environmental concern, with adverse effects on terrestrial and aquatic ecosystems. The HMIs primarily originate from cosmetics, fertilizers, and various chemicals produced from industrial or household waste. Their non-biodegradable characteristics and the potential for accumulation in soft tissues pose significant threats to both humans and the environment. Furthermore, the issue is expected to worsen with rapid industrialization and technological advancements. Silica-based electrodes (SBEs) offer a robust, sensitive, selective, and reliable approach for detecting metal ions, including hazardous pollutants like HMIs. This review provides a comprehensive overview of SBEs, including their types, advantages, working mechanisms, and limitations. Additionally, the fabrication of SBEs and their modifications such as functionalization and hybridization surface modification are critically discussed in constructing high-performance electrochemical HMI sensors. Especially, the review highlights the milestones achieved, remaining shortcomings, and prospects of SBEs in the development of electrochemical sensing devices for HMIs.