A feather duster-like CoFe-LDH/CF composite with parallel array structure as an efficient water splitting electrocatalyst

Abstract

Array structured electrocatalysts represent significant potential for overall water splitting owing to their special spatial arrangement, adjustable properties and chemical stability. Nevertheless, compared to traditional disordered array architectures, few studies focus on electrocatalyst materials with parallel array architectures. Herein, via a novel microfluidic spinning method, we report a feather duster-like cobalt-iron layered double hydroxide/carbon fiber composite electrocatalyst with parallel array architectures (p-CoFe-LDH/CF), in which the needle-like structured cobalt-iron layered double hydroxide perpendicularly aligns on the carbon fiber surfaces. In addition, the feather duster-like fibers possess a hierarchically porous architecture with both micropores and mesopores. In the electrochemical tests, p-CoFe-LDH/CF shows excellent bifunctional activity in an alkaline medium, in which an overpotential of 492 mV at 100 mA cm⁻² for the hydrogen evolution reaction (HER) and 286 mV at 10 mA cm⁻² for the oxygen evolution reaction (OER) is required, even exceeding Pt/C and RuO₂, respectively. The exceptional performance results from rapid electron transportation and increased active sites enabled by this special structure. This research not only proposes an effective synthesis strategy for transition metal-based composites, but also provides structural design guidance for bifunctional electrocatalysts.