Silver Nanomaterial-Doped Layered Double Hydroxides for Advanced Electrochemical Sensing: A Critical Review

Silver-doped layered double hydroxides (Ag-LDHs) have gained prominence as a high-performing class of electroactive materials suited to advanced electrochemical sensors, exhibiting remarkable sensitivity, selectivity, and long-term stability in environmental, biomedical, and food analytical settings. Silver incorporation not only narrows the band gap of the LDH host but also endows the heterostructure with enhanced electrical conductivity, surface reactivity, and rapid redox cycling, clearly outpacing both pure and conventional-metal-doped LDH architectures. These hybrids utilize the inherent ion-exchange capacity and extensive surface area of LDHs, further enhanced by integration with functional materials such as carbon allotropes, metal oxides, and conductive polymers, leading to a synergistic improvement in electrocatalytic performance and mechanical resilience. Despite several studies on these composites, a comprehensive study that critically compares structural designs, synthesis methods, and functional performance in electrochemical sensing is absent. This article addresses that gap by providing a systematic, side-by-side comparison of contemporary Ag-LDH synthetic routes, surface-modification protocols, and sensing metrics. Application-centric evaluations encompass the quantification of pollutants in aqueous matrices, the diagnosis of disease-relevant biomarkers, and the deterrence of unsafe food items. Enduring barriers, including the scale-up of manufacture with consistent quality, stability over extended operational lifetimes, and the realization of cost-competitive fabrication, are rigorously appraised alongside prospective pathways, such as eco-conscious synthesis protocols, hybrid nanoscale architectures, and machine-learning-augmented ideation of sensor designs. Collectively, the compiled findings furnish a coherent roadmap for the translational maturation of Ag-LDH-based electrochemical sensing technologies that transcend proof-of-principle and advance toward the reliable point-of-care deployment beyond controlled laboratory environs.