Molecularly imprinted photoelectrochemical sensing supported by Bi2S3/ Bi2O2CO3 direct Z-scheme heterojunction for aflatoxin B1 detection

An ultrasensitive molecularly imprinted photoelectrochemical (PEC) sensor supported by Bi2S3/Bi2O2CO3 direct Z-scheme heterojunction is constructed for aflatoxin B1 (AFB1) detection. 1D Bi2S3 nanofibers grow over 2D Bi2O2CO3 disks via topotactic transformation by adding thiourea under hydrothemal conditions to form Bi2S3/ Bi2O2CO3 heterostructure. Upon light illumination, the Z-scheme transfer system in Bi2S3/Bi2O2CO3 can favor for the separation of photoinduced carriers, causing higher photocurrent response than pure Bi2O2CO3 and Bi2S3. Aiming at the limited selectivity of PEC sensing, molecularly imprinted polymer (MIP) is introduced to attain the specific recognition of AFB1. Coupling MIP as recognition element with PEC as signal conversion element, the molecularly imprinted PEC sensor shows a linear range of 0.01-1000 ng/mL and a detection limit as low as 2.95 pg/mL. Superior selectivity toward AFB1 is also proven for the sensor. The integration of MIP and PEC supplies a promising strategy for determination of other contamination in food.