Amperometric sensing of hydrogen peroxide via an ITO electrode modified with gold nanoparticles electrodeposited on a CoMn-layered double hydroxide

An electrochemical sensor for hydrogen peroxide (H2O2) has been fabricated by electrodepositing gold nanoparticles (AuNPs) on an indium tin oxide (ITO) electrode modified with cobalt and manganese-layered double hydroxides (CoMn-LDHs). Scanning electron microscopy images reveal well-dispersed AuNPs with a typical size of 12 nm on the surface of the layered double hydroxides. Electrochemical characterizations show that the introduction of the LDH support significantly enhances the voltammetric response to H2O2. This is underpinned by a comparative study that uses single transition metal-LDHs (CoAl-LDHs or MgMn-LDHs) as supports. The results indicate that the presence of binary transition metals in the LDH layer may result in multiple interaction and interfacial effects between AuNPs and the support. At an optimal working voltage of +0.55 V (vs. Ag/AgCl), the sensor displays a wide linear range (0.1 mu M to 1.27 mM), low detection limit (0.06 mu M) and high sensitivity (125.0 mu A.mM(-1).cm(-2)), which are characteristics superior to those of most previously reported AuNP-based composite-modified electrodes. The sensor has good reproducibility and storage stability. In our view, this sensor represents a valuable tool for advanced sensing of H2O2.