Construction of dual electric fields in carbon quantum dots-implanted g-CN piezoelectric polarized heterojunctions for sensitive photoelectrochemical detection of nitrite.

Developing rapid and accurate detection method toward nitrite (NO) in aquatic environment is crucial for human health and ecological safety. However, the accurate quantification of NO is usually hampered by challenges related to sensitivity and selectivity. Herein, a photoelectrochemical (PEC) strategy through the rational design of carbon quantum dots decorated piezoelectric graphitic phase carbon nitride (g-CN-CQDs) heterojunctions was developed for accurate quantification of NO based on the NO triggered diazotization reactions. Experimental analyses reveal that the incorporation of CQDs improves the electronic conductivity, while the build-in interfacial electric field and piezoelectric polarization collectively boost the separation and transfer of photoinduced charge carriers together with suppressed charge recombination. Leveraging this, the proposed PEC strategy that achieves a detection limit of 2.7 nM by modulating electron transport through the diazotization reactions induced by NO on g-CN-CQDs. The developed methodology enables rapid and precise quantification of NO, with promising applications in field of environmental pollution, food quality control and precision health tracking applications.