Preparation of Ag@MnO₂ Nanorods for Colorimetric Detection of Hydroquinone

Rod-shaped MnO₂ was synthesized by hydrothermal method. Ag@MnO₂ NRs were prepared with the Ag nanoparticles grown on the surface of rod-shaped MnO₂ by different reducing agents. The Ag@MnO₂ NRs were characterized by X-ray diffractometry, scanning and transmission electron microscopy, as well as X-ray photoelectron spectroscopy. The catalytic performance, catalytic mechanism and kinetic equation of the Ag@MnO₂ NRs were investigated. The as-prepared Ag@MnO₂ NRs were endowed with oxidase-like activity to catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue product without H₂O₂. Due to the inhibition of hydroquinone (HQ) on TMB oxidation, a simple, rapid, sensitive, and selective colorimetric sensor was set for the detection of HQ concentration in actual water. This method was established with an excellent linear range from 5–30 μM and a low detection limit of 1.7 μM. The colorimetric means could be availably used for the detection of HQ in river water samples and the RSD < 4.97%. The above results illustrated that the Ag@MnO₂ NRs had a great application prospect in environmental detection.