A photoelectrochemical aptasensor based on W-doped carbon nitride with carbon-rich structure for sensitive detection of diazinon.

A photoelectrochemical (PEC) aptasensor us reported based on W-doped carbon nitride with carbon-rich structure (WCCN). WCCN exhibited excellent photoelectric conversion performance owing to the carbon-rich structure and W doping. C atoms can replace the center N/edge N atoms to form a carbon-rich structure, improving the insufficient light absorption of CN in the visible region. Also, W doping forms a directional electron transfer channel, achieving the efficient separation and transport of carriers. W doping and carbon-rich structure can promote the generation, transfer, and separation of photogenerated carriers, further enhancing PEC performance. The fabricated PEC aptasensor based on WCCN demonstrated a wide detection range (3.92 ~ 588 pg L), a low detection limit (1.31 pg L, S/N = 3), good reproducibility, selectivity, stability, and practical application in actual water samples. This work explores the modification strategy of element doping for carbon nitride with high photoelectric property and offers a cost-effective and simplified method for the detection of pesticide residues.