A Cu 2+ -doped two-dimensional material-based heterojunction photoelectrode: application for highly sensitive photoelectrochemical detection of hydrogen sulfide.

In this work, on the basis of a Cu 2+ -doped two-dimensional material-based heterojunction photoelectrode, a novel anodic photoelectrochemical (PEC) sensing platform was constructed for highly sensitive detection of endogenous H 2 S. Briefly, with g-C 3 N 4 and TiO 2 as representative materials, the sensor was fabricated by modifying g-C 3 N 4 /TiO 2 nanorod arrays (NAs) onto the surface of fluorine-doped tin oxide (FTO) and then doping Cu 2+ as a Cu x S ( x = 1, 2) precursor. After the binding of S 2- with surface-attached Cu 2+ , the signal was quenched owing to the in situ generation of Cu x S which offers trapping sites to hinder generation of photocurrent signals. Since the photocurrent inhibition was intimately associated with the concentration of S 2- , a highly sensitive PEC biosensor was fabricated for H 2 S detection. More importantly, the proposed sensing platform showed the enormous potential of g-C 3 N 4 /TiO 2 NAs for further development of PEC bioanalysis, which may serve as a common basis for other semiconductor applications and stimulates the exploration of numerous high-performance nanocomposites.