Layered titanate nanosheets as an enhanced sensing platform for ultrasensitive stripping voltammetric detection of mercury(II)

A highly sensitive and selective Hg(II) sensor has been developed by using layered titanate nanosheets (TNs) as an enhanced sensing platform. The TNs with exchangeable sodium cations located in the interlayer are prepared by a facile hydrothermal route. The as-formed sodium titanate nanosheets (Na-TNs) exhibit a porous nanoarchitectured network. The surface structure and electrochemical performance were systematically investigated. Such a nanostructured TNs-based platform, as a typical cation-exchange material, is highly efficient to capture Hg2+, which dramatically facilitates the enrichment of Hg2+ onto their surface and realizes the stripping voltammetric detection of mercury ions with a remarkably improved sensitivity and selectivity. The detection limit was found to be as low as 5 ppt (S/N = 3), much below the guideline value from the World Health Organization (WHO). The interference from other heavy metal ions such as Cd2+, Mn2+, Ni2+, Pb2+ and Cu2+ ions associated with mercury analysis could be effectively inhibited. Toward the goal for practical applications, the sensor was further evaluated by monitoring Hg(II) in real mushroom samples.