User and eco-friendly pheophorbide a based photoelectrochemical sensor for the detection of phenolic compounds

The development of eco-friendly and cost-effective photoelectrochemical (PEC) sensors for the detection of phenolic compounds is crucial given the increasing concerns surrounding fluorinated photosensitizers (PSs). In this study, the potential of pheophorbide a (PheoA), a natural and commercially available PS, is evaluated for singlet oxygen ( 1 O 2 )-based PEC sensing. PheoA is entrapped in a TiO 2 carrier matrix and deposited onto screen-printed electrodes (PheoA|TiO 2 -SPEs). The sensor is optimised for the detection of hydroquinone (HQ) and 4-aminophenol (4-AP), achieving sub-nanomolar detection limits (23 nM for HQ and 19 nM for 4-AP) under ambient oxygen and LED illumination. Additionally, the PEC response of several phenolic compounds is evaluated. This study highlights the potential of PheoA|TiO 2 -SPEs as highly sensitive, eco-friendly and accessible PEC sensors for phenol detection. • Photoelectrochemical sensing mechanism based on singlet oxygen. • Detection of phenolic compounds via electrocatalytic redox cycling. • User and eco-friendly sensor for phenols based on the use of pheophorbide a. • Sensor provided a sub-nM sensitivity for hydroquinone and 4-aminophenol.