Ordered hollow mesoporous carbon cubes loaded with Au nanoparticles for high-performance electrochemical detection of hexavalent chromium.

Hexavalent chromium (Cr(VI)) seriously damages the ecological environment and human health. Therefore, it is necessary and significant to develop efficient, fast and sensitive detection techniques for Cr(VI). In this work, an electrochemical sensing platform for the determination of Cr(VI) was successfully constructed based on hollow mesoporous carbon cubes loaded with Au nanoparticles (Au@HMCC), which were prepared through a soft template method. By virtue of the chemical etching of ZIF-8 and the carbonization process after coating with mesoporous polydopamine, the products presented a highly ordered hollow mesoporous structure, which provided a large surface area and abundant catalytic active sites for the electrochemical reduction of Cr(VI). Au nanoparticles (AuNPs) were loaded through electrostatic adsorption to further improve the conductivity and amplify the current signal. Consequently, the as-fabricated sensor showed excellent performance in Cr(VI) detection, including a detection limit of 3.0 μg L−1 and a wide linear range from 0.01 μg mL−1 to 112 μg mL−1. The anti-interference, repeatability and stability of the sensor were also satisfactory. Furthermore, the recovery experiment at different concentration levels in real samples and the consistent test results with ICP AES were expected to expand the application scenarios in quantitative analysis of Cr(VI). [Display omitted] • Au@HMCC with highly ordered hollow mesoporous structure was synthesized. • Au@HMCC provided large surface area and abundant catalytic active sites. • AuNPs further improved the conductivity and amplify the current signal. • Au@HMCC/SPCE was successfully fabricated for quantitative analysis of Cr(VI). • The sensor showed a wide linear range and low detection limit. [ABSTRACT FROM AUTHOR]