Three-dimensional Ni foam supported pristine graphene as a superior oxygen evolution electrode

Abstract

Oxygen evolution reaction (OER) represents a major kinetic bottleneck for water splitting. Three-dimensional (3-D) Ni foam (NF) supported pristine few-layer graphene was utilized as an oxygen evolution electrode, showing an overpotential of 382 mV to achieve 10 mA cm−2 and a Tafel slope of 44.9 mV dec−1, both of which are lower than those of pristine NF and graphene and among the lowest reported for carbon and even transition metal-based catalysts measured under the same conditions, and much higher steady-state current density and much less reduction of current density after CV cycling compared to NF and graphene, with negligible current loss after 10 h chronoamperometry and 350 CV cycles. Its high catalytic performance is possibly due to the Ni-promoted OH− adsorption on and uniform dispersion and charge redistribution of the robustly attached graphene. This study not only provides a novel strategy to significantly enhance the OER activity of pristine graphene and creates a high-performance 3-D and binder-free oxygen evolution electrode, but offers scientific insight into the promotion effect of metal supports on the OER activity of pristine graphene.