Tailoring heterostructured Bi2MoO6/Bi2S3 nanobelts for highly selective photoelectrochemical analysis of gallic acid at drug level.

Along with continuous growing widespread adulterations of botanical drugs, the necessity for drug quality monitoring has become more popular than ever. Considering that antioxidants are widely found in natural plant pharmaceuticals, gallic acid (GA) is often regarded as the reference standard to make sure whether these are up to grade as guided by Chinese Pharmacopeia. Herein, a novel Bi2MoO6/Bi2S3 photoelectrochemical sensor has been successfully involved toward selective GA analysis to supervise drug quality, in which γ-Bi2MoO6 nanobelts were treated as template nanocrystal and scaffold. Such Bi2S3 accommodated in Bi2MoO6 nanobelts render platform with excellent light-harvesting capability, selectivity and reproducibility. Concerned mechanism was in-depth pursued through theoretical computation and morphology speculation, inferring that two aspects mainly contribute to the findings: (1) engineering particular structure brings about surface dangling bonds, which raises the likelihood of electrostatic interaction with opposite charges; (2) appending Bi2S3 to the Bi2MoO6 nanobelts acted as a new avenue to mediate photoelectrochemical behavior, nearly devoid of interference effect. Our work opens up broad possibilities for finely distinguishing different antioxidants. As the extension of this simple and valid strategy, photoelectrochemistry will become a potent backing for quality guaranty in drug field, which offers an entry into ensuring good consistency in batch production.