Construction of Ag Nanoparticles-Modified Ultrathin Poly(heptazine Imide) Photosensitization Sensing System for...

The development of ultrasensitive detection of acetaminophen (APAP), an increasingly significant emerging contaminant, is of substantial importance. In this study, we successfully synthesized a well-dispersed Ag nanoparticles (AgNPs) modified ultrathin poly(heptazine imide) nanosheet (Ag/PHI, ∼3.5 nm), which was utilized as a semiconductor in conjunction with eosin Y (EY) to establish a photosensitization detection system achieving ultrasensitive detection of APAP. This system demonstrated a broad visual detection range, covering concentrations from 700 ng·L^-1 to 1 mg·L^-1, with a low limit of detection of 550 ng·L^-1. Furthermore, the system exhibited exceptional selectivity through comparative analyses with other organic contaminants of similar structures and inorganic ions. Nuclear magnetic resonance, in situ technologies, and time-resolved studies have elucidated that Ag/PHI, characterized by its layered crystal structure and suitable energy bands, facilitates the rapid photosensitization decolorization of EY. Additionally, the formation of highly dispersed AgNPs sites significantly enhances the preferential selective adsorption of APAP through interactions between the Ag and carbonyl oxygen, thereby effectively and quantifiably inhibiting the photosensitization decolorization of EY. This approach also proved to be highly suitable for the analysis of real water samples, demonstrating considerable sensitivity and selectivity. This research underscores the application of PHI in a visible light-driven sensing system, enabling trace detection of APAP and highlighting its substantial potential for convenient water monitoring.