Carbon-supported Co(OH)2 coated with Au nanoparticle composites as an efficient catalyst for BH4− electrooxidation

Abstract

Au nanoparticle coated carbon-supported Co(OH)₂ (Co(OH)₂@Au/C) composites are prepared by a two-step method and are used as electrocatalysts for BH₄⁻ electrooxidation. Transmission electron microscopy and X-ray diffraction analysis show that the as-prepared composites are only a few tens of nanometers in size, and the Co(OH)₂ nanoparticles are coated with Au completely. The electrocatalytic activity of the as-prepared composites are tested by cyclic voltammetry, chronoamperometry, chronopotentiometry, and rotating disc electrode voltammetry, and the results show that the Co(OH)₂₍₅₀₎@Au₍₅₀₎/C catalyst shows the highest electrocatalytic activity for BH₄⁻ electrooxidation among the as-prepared composites, and the electron-transfer number related to BH₄⁻ electrooxidation is 5.0 on the Co(OH)₂₍₅₀₎@Au₍₅₀₎/C electrode.