Ni–SiO₂ nanoporous composite as an efficient electrocatalyst for the electrooxidation of hydrogen peroxide

Nickel has attracted much attention as a cheap and readily available electrocatalyst towards the electrooxidation of hydrogen peroxide (H₂O₂). For the electrocatalytic reaction, the larger the surface area of the electrode, the more active sites can be provided, and the better the catalytic performance of the electrode can be achieved. In this paper, a three-dimensional (3D) porous electrode was successfully prepared by a simple two-step method. Firstly, the Ni–SiO₂ composite was uniformly deposited on the carbon paper (CP) by electrodeposition, and then the SiO₂ component in the Ni–SiO₂ composite was removed by after dealloying (AD) to form a Ni–SiO₂/CP (AD) electrode with a 3D porous structure, which has high catalytic activity area and good gas–liquid mass transfer property. The prepared Ni–SiO₂/CP (AD) exhibits superior catalytic activity for H₂O₂ electrooxidation. At normal temperature, Ni–SiO₂/CP (AD) in 1.0 mol dm⁻³ NaOH + 0.2 mol dm⁻³ H₂O₂ electrolyte solution, the oxidation current density reached 355 mA cm⁻², which is 1.85 times the Ni/CP current density under the same conditions. This study provides a new idea for preparation of high catalytic activity of Ni catalyst for the electrooxidation of H₂O₂.