Ultrasensitive Detection of Trace Silver Ions Using MoS₄^2--Intercalated LDH Nanosheets Enhanced SPR Sensor

The widespread use of silver raises concerns about environmental and health risks, necessitating highly sensitive detection methods for trace silver ions (Ag⁺). Surface plasmon resonance (SPR) sensors offer benefits like label-free detection and rapid response, but their sensitivity for Ag⁺ detection is limited due to weak ion adsorption. Here, we developed an SPR sensor with MoS₄^2--intercalated NiAl-layered double hydroxide (LDH) as the adsorption layer of Ag⁺ to enhance detection sensitivity. Our sensor achieves a sensitivity of 254.75 nm/μg/L and detects Ag⁺ at a low concentration of 2.8 pM, outperforming various existing sensors. It also shows excellent repeatability, long-term stability, and selectivity, proving effective in real-world environmental samples. This work advances high-performance SPR sensors for heavy metal ion detection.