Efficient BiVO4 photoanode decorated with Ti3C2TX MXene for enhanced photoelectrochemical sensing of Hg(II) ion.

A highly sensitive photoelectrochemical (PEC) sensing platform was constructed for Hg2+ determination based on the Schottky heterojunction between an emerging 2D material Ti3C2TX MXene and a promising semiconductor material BiVO4. Through simply spin-coating the single-layer Ti3C2TX onto the surface of BiVO4 film, the modified electrode exhibited significantly enhanced PEC activity. However, the boost in photocurrent could be noticeably suppressed due to the consumption of hole-scavenging agents (reduced glutathione) by the added Hg2+. Owing to the selective decrease in the photocurrent with the addition of Hg2+, the PEC sensor based on BiVO4/Ti3C2TX displayed a wide linear range from 1 pM to 2 nM with the limit of detection down to 1 pM. Moreover, the PEC sensor also exhibited satisfactory accuracy and repeatability in practical sample water, the Yangtze River water, demonstrating the great potential for monitoring heavy metal ions in natural water resources.