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Nanotubes of NiCo 2 S 4 /Co 9 S 8 Heterostructure: Efficient Hydrogen Evolution Catalyst in Alkaline Medium
Author(s) -
Basu Mrinmoyee
Publication year - 2018
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201801185
Subject(s) - electrocatalyst , heterojunction , oxygen evolution , catalysis , materials science , nanotube , nanotechnology , water splitting , chemical engineering , hydrothermal circulation , carbon nanotube , chemistry , electrochemistry , photocatalysis , optoelectronics , electrode , organic chemistry , engineering
The most important issue in water splitting is the development of efficient, abundant, and cost‐effective hydrogen and oxygen evolution catalysts. The development of an efficient electrocatalyst for the hydrogen evolution reaction (HER) under alkaline conditions is described here following a simple hydrothermal route. Here, a method for the synthesis of NiCo 2 S 4 /Co 9 S 8 , Co 9 S 8 , and NiCo 2 S 4 nanotubes has been developed. The NiCo 2 S 4 /Co 9 S 8 heterostructure has been introduced as an efficient electrocatalyst towards HER under alkaline conditions (1.0 m KOH). The vertically aligned nanotube heterostructure (NiCo 2 S 4 /Co 9 S 8 ) shows the most efficient activity as compared to bare Co 9 S 8 and NiCo 2 S 4 nanotubes. The heterostructure of NiCo 2 S 4 and Co 9 S 8 shows a significant anodic shift in the onset potential compared to the bare counterpart. NiCo 2 S 4 /Co 9 S 8 can generate a current density of 10 mA cm −2 upon application of only −0.172 V vs. RHE, whereas Co 9 S 8 and NiCo 2 S 4 require −0.293 V and −0.239 V vs. RHE, respectively. The heterostructure formation and the nanotube morphology of Co 9 S 8 and NiCo 2 S 4 facilitates a fast charge transportation which results in higher electrocatalytic activity. The hydrogen gas evolution rate of the NiCo 2 S 4 /Co 9 S 8 heterostructure was determined to be 2.29 μmol min −1 .