Pyrolysis of a self-supported dodecyl sulfate anion-intercalated Co(OH)2 nanosheet with enlarged amorphous phase content toward enhanced activity for alkaline water oxidation
Highly-active electrocatalysts made of earth-abundant elements are vital for efficient and cost-effective energy storage and conversion systems. In this communication, we report the further amorphization of a solvothermally synthesized dodecyl sulfate anions-intercalated cobalt hydroxide nanosheet array on nickel foam (DS-Co(OH)2/NF) via pyrolysis. Owing to the greatly enlarged interlayer distance of DS-Co(OH)2/NF precursor (2.4 nm), and more exposed active sites by enlarged amorphous phase content, the resulting P-DS-Co(OH)2/NF exhibits boosted activity as a 3D catalyst electrode for alkaline water oxidation. In 1.0 M KOH, it needs an overpotential of only 266 mV to drive a geometrical catalytic current density of 70 mA cm−2, 74 and 121 mV lower than those for DS-Co(OH)2/NF precursor and Co(OH)2 without DS anion intercalating (Co(OH)2/NF), respectively. Impressively, this catalyst also displays superior long-term stability with a high turnover frequency value of 0.055 O2 s-1 at an overpotential of 340 mV.