LAUSR

Abstract Graphitic carbon nitride (g-C3N4) is defined as an emerging semiconductor for applications in photocatalytic and photoelectrochemical analysis. In our previous report, it is found that 3D branched crystalline carbon nitride with 1D nanoneedles (3DBC-C3N4) has the features of large surface area, improved light-harvest properties, fast charge mobility, and effective charge separation. Therefore, it could be served as an ideal photoactive material. In this study, the novel photoelectrode (3DBC-C3N4/FTO) exhibits desirable photoelectrochemical behavior towards the reduction of Cu2+. The developed photoelectrochemical sensing platform for detecting trace Cu2+ in aqueous environment shows a linear response ranging from 1 to 100 nM (R2 = 0.9938), with the limit of detection of 0.38 nM (signal-to-noise ratio = 3). Additionally, with the help of density functional theory calculations, the mechanism of selective detection is also explored. This work suggests that such 3D branched structural carbon nitride holds great promises for applying in photoelectrochemical biosensing with high photo-electron conversion efficiency.