A self-powered photoelectrochemical molecular imprinted sensor for chloroquine phosphate with enhanced cathodic photocurrent via stepped energy band alignment engineering

Fabricating a self-powered photoelectrochemical (PEC) sensor with superior performances and cost-effective design is highly desirable but still remains challenges. Herein, we develop a self-powered PEC molecular imprinted (MIP) sensor integrating WO3/TiO2 photoanode and gold nanoparticles modified carbon intercalated MoS2 photocathode for highly sensitive and specific detection of chloroquine phosphate (CQP). By constructing a reasonable stepped energy band structure, the electrons are efficiently transferred driven by the Fermi energy level gap between photoanode and photocathode, which amplifies the cathodic photocurrent. Furthermore, the mechanism of electron transfer driven by the Fermi energy level gap in the self-powered sensor was demonstrated for the first time by density functional theory (DFT). The Molecular imprinted polymer was modified on the photocathode as recognition element, which avoids the interference of reducing substances in the samples and complex biometric reactions. Under optimal conditions, the proposed MIP sensor for CQP presents the detection limit of 0.11 μM with a broad linear range from 10−6 M to 10−3 M. This work presented an innovative design strategy for constructing self-powered sensor.