Facile synthesis of ultrathin two-dimensional graphene-like CeO2–TiO2 mesoporous nanosheet loaded with Ag nanoparticles for non-enzymatic electrochemical detection of superoxide anions in HepG2 cells

Here we presented a new facile strategy to fabricate ultrathin two-dimensional (2D) metal oxide nanosheets , by using polydopamine-coated graphene (rGO@PDA) as a template under simply wet-chemical conditions. Based on the strategy, graphene-like CeO 2 –TiO 2 mesoporous nanosheet ( MNS-CeO 2 -TiO 2 ) was prepared and was loaded with dispersive Ag nanoparticles (AgNPs) to obtain effective electrocatalysts (denoted as Ag/MNS-CeO 2 -TiO 2 ) for electrochemical detection of superoxide anion (O 2 •− ). Characterizations demonstrated that MNS-CeO 2 -TiO 2 exhibited ultrathin thickness, larger specific surface area, and pore volume in comparison with its bulk counterpart. The above properties of MNS-CeO 2 -TiO 2 shorten electron transmission distance, promotes mass transfer, and is conducive to the dispersion of post-modified AgNPs. Therefore, the recommended Ag/MNS-CeO 2 -TiO 2 sensors (denoted as Ag/MNS-CeO 2 -TiO 2 /SPCE ) exhibited satisfactory properties, including the sensitivity of 737.1 μA cm −2 mM −1 , the detection limit of 0.0879 μM (S/N = 3), and good selectivity. Meanwhile, the sensors also successfully realized in the online monitoring of O 2 •− released from HepG2 cells, meaning the prepared sensors had practical application potential towards the analysis of O 2 •− in biological samples.