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

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 mu M) and a low detection limit (0.001 mu M) were observed. The sensor also displayed high stability and acceptable selectivity. It was applied to detect real samples and good results were achieved.