Exploitation of a photoelectrochemical sensing platform for catechol quantitative determination using BiPO4 nanocrystals/BiOI heterojunction.

A photoelectrochemical catechol sensor using BiPO4 nanocrystals/BiOI (BiPO4/BiOI) heterojunction is developed. BiPO4/BiOI heterojunction is fabricated via a simple one-step solvothermal method with KI and ionic liquid 1-octyl-3-methylimidazolium dihydrogen phosphate ([Omim]H2PO4). An enhanced photoelectrochemical separation efficiency is obtained due to the synergistic effect between the formation of BiPO4/BiOI heterojunction and shortening the transmission path of the electron to the surface caused by BiPO4 nanocrystals. Owing to the outstanding photoelectrochemical response of BiPO4/BiOI heterojunction to catechol, a photoelectrochemical sensor is constructed for monitoring catechol. The proposed sensor possesses reliable stability, anti-interference ability and a low detection limit with 2 ng mL-1. The linear range is from 6 to 1.20 × 104 ng mL-1. Notably, this work not only supplies a facile method for BiPO4 nanocrystals based binary heterojunction, but also helps to understand the relationship between BiPO4 nanocrystals and photoelectrochemical performance of binary heterojunction. Convincingly, this strategy can be extended to other BiPO4 nanocrystals based heterojunction and photoelectrochemical sensor platform associated with photoactive materials.