A visible-light-driven photoelectrochemical sensor for the sensitive and selective detection of chlorpyrifos via CoS2 quantum dots/CdS nanowires nanocomposites with 0D/1D heterostructure

A visible-light-responsive photoelectrochemical (PEC) sensor was proposed for the sensitive and selective analysis of chlorpyrifos (CPF) by synergistically using CoS2 quantum dots (QDs) and CdS nanowires (NWs). The CdS NWs were first prepared by the solvothermal method and subsequently combined with CoS2 QDs to produce CoS2/CdS product with 0D/1D heterostructure. It turned out that the so-obtained nanocomposites with 0D/1D heterostructure could greatly suppress the recombination of photoinduced electrons and holes, and the electrode modified with this composite could exhibit preferable PEC performance and photocurrent signal compared to the one with CdS or CoS2. After the addition of CPF, the photocurrent signal of the proposed PEC sensor was found to be selectively decreased because of the specific chelation between the cobalt sites of CoS2/CdS and the sulfur, nitrogen-atoms of CPF, which might block the electrons transferring process. The proposed PEC sensor could detect CPF in concentrations that linearly span from 0.030 to 100 ppb with an ideal detection limit of 0.010 ppb, which performances are much better than those of currently used analytical methods. Furthermore, this work may establish a framework for the development of various PEC sensing platforms with 0D/1D heterostructure for the quantitative assay of environmental pollutants like CPF.