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Highly efficient oxygen evolution from CoS2/CNT nanocomposites via a one-step electrochemical deposition and dissolution method

journal contribution
posted on 25.05.2017, 00:00 authored by J Yang, Z Yang, Luhua LiLuhua Li, Qiran CaiQiran Cai, H Nie, M Ge, X Chen, Ying (Ian) ChenYing (Ian) Chen, S Huang
The oxygen evolution reaction (OER) has been viewed as a critical step in electrochemical energy conversion and storage devices. However, searching for cheap and efficient OER electrocatalysts still remains an urgent task. Herein, we develop a new strategy involving a one-step electrochemical deposition and dissolution method to fabricate hydrophilic porous CoS2/carbon nanotube (CNT) composites (CNT-CoS2). X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy measurements confirm the formation of hydrophilic groups on the surface of the porous CoS2 during electrochemical oxidation. Our design holds several advantages. The electricity conductivity of CoS2 is increased by introducing CNTs as a conductive substrate. The porous nanostructures of CoS2 increase its surface area, and provide paths to promote charge and reactant transfer. The active edge sites modified with hydrophilic groups can increase the content of electrolyte-electrode contact points, increasing the intrinsic catalytic performance of CoS2. These factors allow CNT-CoS2 to achieve a low onset potential of 1.33 V vs. RHE, a stable current density (j) of 10 mA cm(-2) at an overpotential of 290 mV, and excellent stability under alkaline conditions compared to that of IrO2. The comprehensive performance of the CNT-CoS2 electrocatalyst is comparable to or better than that of any reported noble metal-free OER catalyst, even RuO2 and IrO2. This facile synthesis strategy involving synchronous electrochemical deposition and dissolution should be easily adapted for large-scale water electrolysis.

History

Journal

Nanoscale

Volume

9

Issue

20

Pagination

6886 - 6894

Publisher

Royal Society of Chemistry

Location

Cambridge, Eng.

eISSN

2040-3372

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2017, Royal Society of Chemistry