Highly sensitive and selective photoelectrochemical detection of bis(2-ethylhexyl)phthalate on broad-spectrum responsive and interfacial electronic interaction induced p-n BiOI/ZnO nanoarrays heterojunction.

Bis(2-ethylhexyl)phthalate (DEHP), an endocrine disruptor, shows carcinogenic, teratogenic, mutagenic and estrogenic effects. It is easy to release from plastic materials and migrate to soil environment, causing serious pollution and posing a great threat to human health. In our work, a photoelectrochemical (PEC) sensing platform for DEHP detection was constructed using BiOI/ZnO nanoarrays (NRs) as the transducer species and the DEHP aptamers as the biological recognition elements. ZnO NRs with three-dimensional and large diameter area were prepared by hydrothermal method to increase the light absorption capacity. Coupling BiOI in a narrow band gap with ZnO NRs strengthened visible-light absorption, while promoting charge carrier separation and transportation. This was attributed to the generation of an internal electric field between BiOI and ZnO NRs, exhibiting obvious photocurrent response. The as-developed PEC sensing platform demonstrated great sensing performance for detection of DEHP. Furthermore, the photocurrent varied and the logarithm of DEHP concentration showed a linear relationship from 1.0 × 10-11 to 5.0 × 10-7  mol/L, and the limit of detection was estimated to be 3.8 × 10-12  mol/L. In the meantime, while evaluating its usage in real soil samples, satisfying outcomes were realized. Thus, the as-proposed PEC sensing platform provided a potential device to monitor DEHP in the environment.