Mass and Charge Transfer Coenhanced Oxygen Evolution Behaviors in CoFe‐Layered Double Hydroxide Assembled on Graphene

Abstract

The earth‐abundant electrocatalysts with high activity are highly desired and required for high‐efficient oxygen evolution reaction (OER). Herein, we report that 2D nanosheet‐shaped cobalt–iron‐layered double hydroxide (CoFe‐LDH) is a highly active and stable oxygen evolution catalyst. The Fe3+ is capable of tailoring the component ranging from hydroxides to LDH and broadening the interlayer space of as‐made 2D materials. Benefiting from the synergistic effects between Co and Fe species and the LDH‐layered structure, the shortened ion transport distance in the nanoscale dimension, and the broader interlayer space, an enhanced mass transfer behavior for OER is demonstrated. The as‐made CoFe‐LDH shows high electrocatalytic activity, which is superior to those of corresponding Co(OH)2 and the mixed phase samples of Co(OH)2 and FeOOH, as well as RuO2 and commercial Pt/C catalysts. Assembling CoFe‐LDH on reduced graphene oxide (rGO) to configure the 2D sheet‐on‐sheet binary architectures (CoFe‐LDH/rGO) can further create well‐interconnected conductive networks within the electrode matrix, leading to the lowest overpotential of 325 mV at 10 mA cm−2. Collectively, such integrated characteristics with alternated components will endow the as‐made 2D‐structured catalysts with a potential and superb superiority as low‐cost earth‐abundance catalysts for water oxidation.