Sensitive photoelectrochemical detection of Cr(Ⅵ) based on the suppression of background photocurrent

Abstract

A photoelectrochemical (PEC) sensor based on a BiVO₄ semiconductor and gold nanoparticles (AuNPs) was successfully prepared for the sensitive detection of Cr(Ⅵ) ions. The calcination temperature was found to be very important for the PEC properties of BiVO₄. The BiVO₄-modified indium tin oxide electrode (ITO/BiVO₄) calcined at 300 °C generated a low cathodic photocurrent response under light irradiation. BiVO₄/AuNPs materials were coupled via electrostatic adsorption to enhance the photoelectric conversion performance of BiVO₄. The use of self-assembled monolayers (SAMs) to modify electrodes reduce the background current. The developed ITO/BiVO₄/AuNPs/L-Cys PEC sensor was used to detect of Cr(VI). The Cr(Ⅵ) ion concentrations showed a good linearity between 10 pM and 1 μM with a detection limit of 9.1 pM (S/N = 3). The prepared PEC sensor exhibited high sensitivity, a wide linear range, and good selectivity. This work provides a promising platform for the analytical detection of heavy metal ions.