Effect of Concentration and pH of GO Solutions on the Pd-rGO@NF Electrode Prepared by Spontaneous Reduction for H2O2 Reduction in Acidic Media

The Pd-rGO@NF composite electrodes were prepared by a simple and green two-step process of spontaneous reduction. Graphene oxide (GO) was first reduced directly by nickel foam (NF) to form a rGO@NF composite substrate. The effect mechanism of GO concentration and pH on the morphology and properties of rGO@NF was investigated by SEM, TEM, XRD and Raman. Increasing GO and H+ concentration can improve the reduction rate, deposit amount and reduction degree of GO on the surface of Ni foam. A uniform, compact and multi-fold rGO coating formed on the Ni skeleton surface at the GO concentration of 2gL(-1) and pH of 7. Then, Pd2+ was reduced by rGO on the NF surface to construct the 3D Pd-rGO@NF composite electrodes, which showed superior catalytic activity and stability for H2O2 reduction in acidic media compared to Pd-NF due to a higher surface area and better anti-acid corrosion from rGO layers.