Graphitic carbon nitride solid nanofilms for selective and recyclable sensing of Cu²⁺ and Ag⁺ in water and serum

Herein we report the fabrication of g-C₃N₄ nanofilms and their application as a solid fluorescence sensor. The as-prepared films are capable of convenient, sensitive, selective, rapid and recyclable sensing of Cu²⁺ and Ag⁺ in water and serum, indicating the sensor's potential application in disease diagnosis. Attractively, our sensor is able to differentiate Cu²⁺ and Ag⁺ by making use of their different adsorption and desorption kinetics during the interaction with g-C₃N₄ nanofilms.