Recent advances in pristine/heterojunction bismuth tungstate-based (photo)electrochemical sensing strategies

Photoelectrochemical (PEC) sensors, which combine photocatalytic and electrochemical properties, have become a novel analytical tool. A PEC sensor's notable benefits include in-situ analyses, easy construction, portability, exceptional sensitivity, and cost-effectiveness. This review article presents bismuth tungstate-based electrochemical and photoelectrochemical sensors. Electrochemical sensors include pristine Bi 2 WO 6 -based sensors and rGO-Bi 2 WO 6 composite-based sensors. Photoelectrochemical sensors are divided into five sections: pristine Bi 2 WO 6 -based sensors, Bi 2 WO 6 heterojunction-based sensors, Bi 2 WO 6 heterojunction-based sensors with hole-trapping agent, Bi 2 WO 6 heterojunction-based label-free biosensors, and Bi 2 WO 6 heterojunction-based sandwich-biosensors. Different heterojunctions have been obtained by associating narrow bandgap semiconductors (WO 3 , CuS, Fe 2 O 3 , Bi 2 S 3 , Ag 2 S, BiOBr, CuS, MoS 2 , CdS), conductive carbon materials (g-C 3 N 4 , RGO), metallic nanoparticles (Au,Ag), or conductive polymers (polypyrrole, polydopamine) with Bi 2 WO 6 crystals. Many sensors and biosensors provide a signal-on detection, whereas some sensors and biosensors, associated with a hole-trapping agent (ascorbic acid, hydrogen peroxide, sulfate), lead to a signal-off detection. Many molecules of health interest (metabolites, biomarkers, drugs) and a few pollutants have been detected with low detection limits. Additionally, the challenges for further large-scale applications of Bi 2 WO 6 -based sensors in the fields of health and environmental control are analyzed. • Bismuth tungstate is an efficient photocatalyst due to its light absorption properties. • Pristine Bi 2 WO 6 and Bi 2 WO 6 -rGO composite-based electrochemical sensors are described. • Pristine Bi 2 WO 6 and Bi 2 WO 6 heterojunction-based photoelectrochemical sensors are described. • Bi 2 WO 6 heterojunction-based label-free and sandwich biosensors are described. • Summary and prospects conclude the review manuscript.