Highly sensitive and selective photoelectrochemical sensor for mercury(II) detection based on efficient Bi2MoO6 photoanode decorated with CuS

Highlights: • An efficient Bi₂MoO₆/CuS photoelectrochemical sensor was synthesized. • The Bi₂MoO₆/CuS composites have the excellent PEC performance. • The PEC sensor exhibited outstanding performances for mercury (II) detection. -- Abstract: Stronger photocatalytic activity and better photoelectrochemical (PEC) performance can Bi2MoO6/CuS photocatalyst accomplish compared to that of pure Bi2MoO6. CuS was also conducive to strengthen the visible light absorption and inhibited the recombination of electron-hole pairs. The addition of glutathione (GSH) in the electrolyte led to a significant enhancement to the reactivity of the PEC sensor in the modified electrode. In contrast, the increase in photocurrent was restrained to a high degree for that the hole scavenging agents were consumed through the addition of mercury (Hg²⁺). Consequently, the electrode was able to be exploited for Hg2+ detection even though no specific identification component was introduced yet. The wide linear range of 0.5 nM–230 nM and low detection limit of 0.23 nM made the electrode adaptable to the detection of Hg2+ in practical samples. Thanks to a ameliorative PEC performance, thus, the Bi2MoO6/CuS sensor stands a good chance to play a useful part in the detection of Hg2+.