A strongly coupled Au/Fe3O4/GO hybrid material with enhanced nanozyme activity for highly sensitive colorimetric detection, and rapid and efficient removal of Hg2+ in aqueous solutions

Abstract

We have developed an efficient strategy for synthesizing a strongly coupled Au/Fe₃O₄/GO hybrid material to improve the catalytic activity, stability, and separation capability of Au nanoparticles (NPs) and Hg²⁺. The hybrid material can be synthesized by the direct anchoring of Au and Fe₃O₄ NPs on the functional groups of GO. This approach affords strong chemical attachments between the NPs and GO, allowing this hybrid material to ultrasensitively detect Hg²⁺ in aqueous solutions with a detection limit as low as 0.15 nM. In addition, the deposition of Hg⁰ on the surface of Au/Fe₃O₄/GO could be quickly (within 30 min) and efficiently (>99% elimination efficiency) removed by the simple application of an external magnetic field and then Au/Fe₃O₄/GO could be subsequently reused at least 15 times, with the elimination efficiency remaining high (>96%).