Oxygen vacancies and Bi2S3 nanoparticles co-sensitized TiO2 nanotube arrays for enhanced photoelectrochemical sensing of chlorpyrifos

Due to the environmental pollution and food safety problems that caused by the abuse of chlorpyrifos (CPF), a strategy of which is detected with high efficiency is urgently demanded. Herein, a photoelectrochemical sensor which using TiO 2 nanotube arrays with oxygen vacancies (V o -TNTAs) as electrode was constructed. Oxygen vacancies are introduced into TNTAs in order to generate a new defect level that narrows its band gap. The bismuth sulfide nanoparticles are loaded on V o -TNTAs to accelerate the separation of electron-hole pairs. Thus, the Bi 2 S 3 /V o -TNTAs hetero-structure is designed and constructed. With the existence of CPF, a complex which composed by Bi ions and CPF will be formed in situ to block the electrons transfer from electron donor (ascorbic acid) to Bi 2 S 3 , causing the weakened photocurrent. Consequently, the Bi 2 S 3 /V o -TNTAs electrode possess higher photocurrent response than that of pure V o -TNTAs and TNTAs. The Bi 2 S 3 /V o -TNTAs-based PEC sensor displays a linear range of 0.07–3.0 μmol/L with a detection limit of 6.0 nmol/L (S/N = 3) and can be utilized for CPF detection in lettuce and cucumber samples with recoveries of 95.7 to 110 %.