A novel three-dimensional gold catalyst prepared by simple pulse electrodeposition and its high electrochemical performance for hydrogen peroxide reduction

Abstract

Novel Au nanoparticles (NP), Au pinecones (PC) and Au nanodendrites (ND) supported on carbon coated titanium dioxide (C@TiO₂) nanoarrays were successfully obtained through a facile chemical vapor deposition of three-dimensional (3D) C@TiO₂ substrate, followed by potential pulse electrodeposition of Au electrocatalysts. The morphology and structure of the open 3D Au–C@TiO₂ electrodes was characterized by scanning electron microscopy and X-ray diffractometry. The different morphology of electrodeposited Au can be easily controlled by the applied potential (E_o). Electrochemical methods, including cyclic voltammetry, linear sweep voltammetry and chronoamperometry, were used to examine the catalytic activity of the electrode for H₂O₂ electroreduction in H₂SO₄ solution. The Au ND–C@TiO₂ electrode exhibited the largest effective specific surface area among the Au–C@TiO₂ electrodes, owing to its open nanodendritic structure allowing the full utilization of Au surface active sites. A nearly constant reduction current density of 0.655 A cm⁻² was successfully achieved on the Au ND–C@TiO₂ electrode at the potential of 0 V in 2.0 mol L⁻¹ H₂O₂ + 2.0 mol L⁻¹ H₂SO₄ solution, which was significantly higher than the catalytic activity of H₂O₂ electroreduction achieved previously with precious metals as catalysts.