Self-powered photoelectrochemical sensor based on porous carbon nitride by a simple precursor pretreatment strategy as photoanode for Pb2+ detection

Abstract

Ensuring food safety and environmental protection requires the rapid detection of lead ion (Pb²⁺), an additive frequently utilised in industrial and domestic applications. Herein, a self-powered photoelectrochemical sensor (SPES) was constructed by integrating a photocatalytic hydrogen peroxide fuel cell (PFC) with an electrochemical sensor. Unlike traditional electrochemical sensor, this SPES relies not only on the band gap of the photoanode but also on the efficient separation and transportation of the photogenerated carriers. The porous carbon nitride (HE-CN) was prepared using a simple precursor pretreatment strategy, which provides more reactive sites and achieves more efficient separation and transport of photogenerated carriers than bulk carbon nitride (CN) produced by conventional method. Using the mechanism of photoanode adsorption of Pb²⁺, HE-CN was designed as the photoanode material,which greatly enhances the output energy of the SPES. Under ideal test conditions, the SPES demonstrated a low detection limit of 0.42 nM (Signal-to-noise ratio (S/N) = 3) for Pb²⁺ and a linear response concentration range from 0.01 to 1.5 μM, with a correlation coefficient of 0.9918, and the spiked recovery rate is between 96.2 % and 106.8 %. Therefore, the SPES platform exhibits excellent stability, good reproducibility,as well as a high sensitivity in detecting Pb²⁺.