Green-synthesized nanoparticle-enhanced electrochemical sensors for Pb and Cd ions detection

Abstract

The widespread occurrence of toxic heavy metals, such as lead (Pb) and cadmium (Cd), poses a significant threat to both ecological and human health because of their high toxicity, persistence, and bioaccumulation. In response to the urgent need for sustainable and sensitive detection strategies, this review critically evaluates recent advances (2015–2025) in the green synthesis of nanoparticles (NPs) and their correlation with sensor performance. Nanoparticles synthesized via environmentally friendly routes using plant extracts, microbial systems, and natural polymers exhibit tunable physicochemical properties that enhance the sensitivity, selectivity, and detection limits of sensors. We examine the integration of these nanomaterials into electrochemical platforms, focusing on their structural features, synthesis mechanisms, and performance in heavy metal ion detection. Comparative insights into the synthesis approaches and NPs compositions are provided to elucidate the structure–function relationships that dictate the sensing behavior. We also discuss key challenges related to the scalability of green synthesis, electrode stability, and long-term reproducibility. This review concludes with perspectives on the future deployment of green-enabled sensors for real-time, on-site environmental monitoring, emphasizing their potential for sustainable, high-performance solutions in heavy metal detection.