A type I Bi2S3@ZnS core–shell structured photocatalyst for the selective photoelectrochemical sensing of Cu2+

Abstract

A type I core/shell structured Bi₂S₃@ZnS photocatalyst was synthesized by an electrostatic interaction mechanism and used for the photoelectrochemical detection of Cu²⁺. The Bi₂S₃@ZnS composite showed excellent photoelectrochemical activity and stability due to the high photoelectrochemical activity of Bi₂S₃ and the anti-photocorrosion function of the ZnS shell. In addition, the ZnS shell also provided a transfer platform for the photogenerated holes through its acceptor states (i.e. V_Zn and I_S) and suppressed the recombination of photogenerated carriers. The photocurrent signal of the obtained Bi₂S₃@ZnS/ITO electrode was much higher than that of pure Bi₂S₃ under visible-light irradiation. When it was used for the photoelectrochemical sensing of Cu²⁺, a wide detection range (0.003–30.0 μM) and a low detection limit (0.001 μM) were observed. The sensor also displayed high stability and acceptable selectivity. It was applied to detect real samples and good results were achieved.