A self-powered photoelectrochemical sensor based on Cs3Bi2Br9/BiOBr photocathode for acetamiprid detection in vegetables

A handily self-powered photoelectrochemical (PEC) sensor is established for acetamiprid (ACE) analysis supported by Cu 3 Mo 2 O 9 /Ag 2 S photoanode and Cs 3 Bi 2 Br 9 /BiOBr photocathode. The band gap structure of Cu 3 Mo 2 O 9 and Ag 2 S is matched which enhanced the electron transfer rate. Photocathode composite is synthesized at the interface of water and oil, and the resulting composite has good stability to water and light. Electrons flowing from the photoanode through the external circuit to the photocathode can combine with photogenerated holes of Cs 3 Bi 2 Br 9 /BiOBr, causing the photoelectrons pass into the solution and react with oxygen, and producing a large photocathode current. With the increase of ACE concentration, the detected photocurrent gradually decreased due to the steric hindrance, and a linear relationship between photocurrent and ACE concentration in the range of 0.001–500 nM. This excellent PEC sensor also performed the great detection stability, selectivity and reproducibility, which can also be applied in practical application for pesticides analysis.