Selective and visible-light-driven profenofos sensing with calixarene receptors on TiO2 nanotube film electrodes

Highly selective and sensitive determination of profenofos (PFF) is achieved by fast and convenient visible-light-driven photoelectrochemical (PEC) sensor with a low detection limit of 1 nM (S/N = 3). The sensor is fabricated on highly ordered and vertically aligned TiO2 nanotubes (NTs) employing p-tert-butylcalix[4]arene (CA) as recognition element and visible-light sensitizer. It shows excellent selectivity towards PFF, and 100-fold excess of coexistent interferences only causes minor changes of the photocurrent of PFF. Mechanism study suggests that this high selectivity may be attributed to the specific binding ability of CA to PFF, and it is further confirmed by molecular docking calculations. The best binding mode between CA and PFF is also proposed.

► Direct PEC sensing of profenofos in water samples is achieved with CA@TiO2 NTs.
► CA is employed as recognition element and improves the sensor selectivity greatly.
► CA also works as visible-light sensitizer of TiO2 NTs.
► The PEC sensor shows good stability and repeatability in detection of profenofos.