A Cu2+-doped two-dimensional material-based heterojunction photoelectrode: application for highly sensitive photoelectrochemical detection of hydrogen sulfide

Abstract

In this work, on the basis of a Cu²⁺-doped two-dimensional material-based heterojunction photoelectrode, a novel anodic photoelectrochemical (PEC) sensing platform was constructed for highly sensitive detection of endogenous H₂S. Briefly, with g-C₃N₄ and TiO₂ as representative materials, the sensor was fabricated by modifying g-C₃N₄/TiO₂ nanorod arrays (NAs) onto the surface of fluorine-doped tin oxide (FTO) and then doping Cu²⁺ as a Cu_xS (x = 1, 2) precursor. After the binding of S²⁻ with surface-attached Cu²⁺, the signal was quenched owing to the in situ generation of Cu_xS which offers trapping sites to hinder generation of photocurrent signals. Since the photocurrent inhibition was intimately associated with the concentration of S²⁻, a highly sensitive PEC biosensor was fabricated for H₂S detection. More importantly, the proposed sensing platform showed the enormous potential of g-C₃N₄/TiO₂ 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.