Ruthenium-loaded cerium dioxide nanocomposites with rich oxygen vacancies promoted the highly sensitive electrochemical detection of Hg(II)

Metal oxides nanomaterials are limited in electrochemical detection of heavy metal ions (HMIs) because of their poor conductivity and less active sites, which hinders electron transport and reduce the redox rate of HMIs, making it difficult to achieve sensitive and accurate detection of trace pollutions. Herein, Ru-loaded cerium dioxide nanocubes (Ru/CeO2) with rich oxygen vacancies (OVs) was developed to construct electrochemical sensing interface. An unexpected sensitivity of up to 2169.8 μA μM−1 cm-2 was obtained with a detection limit of 0.019 μM in the detection of Hg(II). The predominantly exposed highly active (100) crystal facets and abundant OVs on the surface of CeO2 nanocubes, as well as Ru nanoparticles with excellent metal activity, providing large amounts of reactive oxygen species and active sites, thereby enhancing the conductivity and adsorption capacity of the nanocomposites. Ultimately, the outstanding electrochemical signal was achieved by promoting the redox reaction of Hg(II). In addition, the proposed method shows the excellent stability and high anti-interference ability, and the accurate analysis of Hg(II) in real water samples was realized. This finding provides a good strategy for the development of nano-metal oxide with OVs for the reliable determination of trace heavy metal substance.