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Rational Design and Synthesis of Extremely Efficient Macroporous CoSe 2 –CNT Composite Microspheres for Hydrogen Evolution Reaction
Author(s) -
Kim Jin Koo,
Park Gi Dae,
Kim Jung Hyun,
Park SeungKeun,
Kang Yun Chan
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201700068
Subject(s) - tafel equation , overpotential , materials science , composite number , carbon nanotube , chemical engineering , nanoparticle , microsphere , nanocrystal , nanotechnology , electrode , composite material , electrochemistry , chemistry , engineering
Uniquely structured CoSe 2 –carbon nanotube (CNT) composite microspheres with optimized morphology for the hydrogen‐evolution reaction (HER) are prepared by spray pyrolysis and subsequent selenization. The ultrafine CoSe 2 nanocrystals uniformly decorate the entire macroporous CNT backbone in CoSe 2 –CNT composite microspheres. The macroporous CNT backbone strongly improves the electrocatalytic activity of CoSe 2 by improving the electrical conductivity and minimizing the growth of CoSe 2 nanocrystals during the synthesis process. In addition, the macroporous structure resulting from the CNT backbone improves the electrocatalytic activity of the CoSe 2 –CNT microspheres by increasing the removal rate of generated H 2 and minimizing the polarization of the electrode during HER. The CoSe 2 –CNT composite microspheres demonstrate excellent catalytic activity for HER in an acidic medium (10 mA cm −2 at an overpotential of ≈174 mV). The bare CoSe 2 powders exhibit moderate HER activity, with an overpotential of 226 mV at 10 mA cm −2 . The Tafel slopes for the CoSe 2 –CNT composite and bare CoSe 2 powders are 37.8 and 58.9 mV dec −1 , respectively. The CoSe 2 –CNT composite microspheres have a slightly larger Tafel slope than that of commercial carbon‐supported platinum nanoparticles, which is 30.2 mV dec –1 .