A photoelectrochemical sensor for highly selective detection of tert-butylhydroquinone based on Z-scheme heterojunction electron transport channel of SnIn4S8 hierarchical microsphere nanoflower assembled Bi2O3 pyramid

Tert -Butylhydroquinone (TBHQ) is a phenolic antioxidant commonly found in edible oils. However, excessive amounts of TBHQ can adversely affect food quality due to its toxic and mutagenic effects, which may cause human injury and present carcinogenic risks. Thus, there is an urgent need to develop a sensitive and accurate analytical method for the rapid detection of TBHQ. In this work, hierarchical flower-structured spherical SnIn 4 S 8 and pyramidal Bi 2 O 3 were combined to obtain the Z-scheme SnIn 4 S 8 /Bi 2 O 3 heterojunction. Under irradiation, the electron transport channel of this heterojunction facilitated the combination of electrons in the conduction band of Bi 2 O 3 with holes in the valence band of SnIn 4 S 8 , which decreased the recombination rate of photogenerated electrons and improved the photoelectric response. After the addition of TBHQ, the adsorption effect on the electrode surface and the oxidation reaction with holes in the valence band of Bi 2 O 3 further promoted the charge transfer and separation of photogenerated electrons and holes, which led to a rapid increase in the photocurrent to realize the detection of TBHQ in environmental and food samples. The increase in photocurrent has been linearly correlated with the logarithm of the concentration of TBHQ in the range of 1.00–500 μM with a limit of detection of 0.526 μM. Furthermore, the sensor showed excellent selectivity in the presence of a wide range of analogs. This study provides a novel scheme for the precise detection of TBHQ and the construction of high-performance photoelectrochemical Z-scheme heterojunctions.