Cobalt-doped cerium oxide nanocrystals shelled 1D SnO structures for highly sensitive and selective xanthine detection in biofluids.

In this study, we prepared a three-dimensional self-supported electrocatalyst based on a thin layer of cerium oxide nanocrystals doped with cobalt heteroatoms (CeO-Co) and then uniformly shelled over one-dimensional tin oxide (SnO) nanorods supported by carbon cloth substrate. The material was used as a binder-free sensor that could nonenzymatically detect xanthine (XA) with an excellent sensitivity of 3.56 μA μM, wide linear range of 25 nM to 55 µM, low detection limit of 58 nM, and good selectivity. A screen-printed electrode based on the material accurately detected XA in food samples as well. The achievements were resulted from synergistic effects coming from the unique core@shell formation and Co-doping strategy, which efficiently modified electronic structure of the material to expose more electroactive site numbers/types and fast charge transfer, thereby producing intrinsic catalytic properties for XA oxidation. These results suggested that the SnO@CeO-Co is potential for developing efficient sensor to detect XA with good sensitivity and accuracy in food-quality monitoring.