Grain-boundary-rich high-entropy selenide combining with hollow cerium-doped CoMn2O4 nanocubes for enhanced photoelectrochemical aptasensing

Sulfadimethoxine (SDM) is an antibiotic used in treating bacterial infections, but it poses health risks if it enters human body through food chains. In this study, a grain-boundary-rich high-entropy selenide (CdCoCuMnZn) x Se was prepared by a one-pot solvothermal strategy. Its microstructure, photoactivity and photostability were investigated using various techniques, whose dynamic mechanism was elucidated and the role of elemental doping in enhancing photoelectrochemical (PEC) performance was rigorously evaluated in control groups. For the first time, this high-entropy selenide was applied to construct a PEC aptasensor for highly sensitive and selective SDM detection. A signal amplification strategy was implemented using ferrocene-functionalized hollow cerium-doped CoMn 2 O 4 nanocubes (Ce-CoMn 2 O 4 -Fc). The PEC biosensor exhibited a broad linear range from 0.01 to 1000 ng mL −1 and a low detection limit of 1.2 pg mL −1 . The sensor was successfully used to detect SDM in milk and water samples, yielding reliable results. This work provides constructive insights into PEC sensor development using the high-entropy material and Ce-CoMn 2 O 4 -Fc for enhanced performance. It demonstrates significant potential applications in environmental risk assessment and food safety monitoring using multicomponent materials.