A high-performance light-driven photoelectrochemical sensor based on CdIn2S4/b-TiO2/GO type-II 2D/3D heterojunction for the detection of baicalein in natural plant samples

[Display omitted] •The CdIn2S4/b-TiO2/GO exhibits excellent photoelectrochemical properties.•The 2D/3D heterojunction can inhibit the recombination of electron/hole.•This sensor exhibites an ultra-low LOD of 0.5 nM for baicalein.•The photoelectrochemical sensing mechanism of baicalein has been investigated. The remarkable pharmacological activities of flavonoids and their effects on human health have prompted many studies. To solve the problem that flavonoids are difficult to be accurately quantified, a novel photoelectrochemical (PEC) sensor based on CdIn2S4/b-TiO2/GO was created to detect the baicalein (BCA). By using physical ultrasonic compounding, a straightforward and effective CdIn2S4/b-TiO2/GO composite was created. The composite’s photoelectric effect was 14 times greater than that of the individual material. When BCA was present, a flavonoid-TiO2 nanoconjugate was formed based on the interaction between b-TiO2 and BCA. This interaction prevented the formation and decreased charge transfer of photoporous holes, resulting in a significant decline in photocurrent. Therefore, the PEC sensor based on the change of the electrode surface state can realize the sensitive detection of BCA. The PEC sensor has a wide linear detection range of 1 nM − 30 μM with a limit of detection of 0.5 nM. In addition, the sensor has exhibited excellent accuracy in detecting BCA in the roots and leaves of Scutellaria baicalensis, which can be used for the detection of actual samples.