An active nanoporous Ni(Fe) OER electrocatalyst via selective dissolution of Cd in alkaline media

Although there has been a significant progress regarding electrocatalysts for the electrochemical oxygen evolution reaction, further breakthroughs are still required due to its sluggish 4-electron transfer mechanism. Ni is considered as a potential candidate for the oxygen evolution reaction (OER) in alkaline media in lieu of noble metals, however, the utility of Ni has been limited by the required and relatively high overpotentials. In this study, we fabricated a nanoporous Ni structure by selective and partial dissolution of Cd from a NiCd composite (without using hazardous acids or bases). The formation of nanoporous Ni greatly enhanced OER performance because of the increased number of catalytic sites. Furthermore, there was a promotional electronic effect on the electrocatalyst induced by Cd atoms under the Ni surface tuning the catalytic reactivity could be tuned. Additionally, Fe deposition on the porous Ni-Cd structure significantly raised the OER activity via a reduction in the overpotential from a value of η = 382 mV (before Fe deposition) to η = 290 mV (after Fe deposition) to achieve 10 mA cm−2.