Superlattice-Like Co-Doped Mn Oxide and NiFe Hydroxide Nanosheets toward an Energetic Oxygen Evolution Reaction
Ying Zhang, Xia Long, Xiaohe Liu, Gen Chen, Ning Zhang, Mimi Li, Renzhi Ma, Hao Wan
Abstract
Designing efficient electrocatalysts without noble metals is an imperative challenge for the oxygen evolution reaction (OER) application used in the water-splitting field. However, the low catalytic stability and conductivity impede the industrial application. Herein, the cobalt-substituted manganese oxide (MnCo-O) monolayer nanosheet was exfoliated via intercalation, and the nickel iron double hydroxide (NiFe-OH) nanosheet served as a highly active composition. The oppositely charged MnCo-O and NiFe-OH nanosheet would stack into the superlattice (MnCo/NiFe) with alternating layers of ∼1 nm. Using potassium hydroxide (KOH) solution as the electrolyte, the MnCo/NiFe composite material delivered superior OER performances, which showed a small overpotential (233 mV) at current density of 10 mA cm−2 and low Tafel slope (46 mV dec–1). Such a catalyst could further present long-term catalytic durability of more than 50 h with almost no attenuation. This study develops a scalable strategy to simultaneously achieve a distinctive structure at a low cost for a high-performance noble-metal-free electrocatalyst.