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CoSe 2 /MoSe 2 Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction
Author(s) -
Zhao Guoqiang,
Li Peng,
Rui Kun,
Chen Yaping,
Dou Shi Xue,
Sun Wenping
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201801693
Subject(s) - dissociation (chemistry) , overpotential , adsorption , catalysis , electrolysis of water , heterojunction , water splitting , electrochemistry , inorganic chemistry , materials science , hydrogen , chemical engineering , electrocatalyst , chemistry , electrolysis , photocatalysis , electrode , electrolyte , organic chemistry , optoelectronics , engineering
Abstract Transition‐metal dichalcogenides (TMDs) are promising electrocatalysts toward the hydrogen evolution reaction (HER) in acid media, but they show significantly inferior activity in alkaline media due to the extremely sluggish water dissociation kinetics. Herein, CoSe 2 /MoSe 2 heterostructures with CoSe 2 quantum dots anchored on MoSe 2 nanosheets are synthesized towards enhanced alkaline HER catalytic activity. The incorporation of CoSe 2 is intended to construct additional water adsorption sites on the basal planes of MoSe 2 to promote water dissociation. The CoSe 2 /MoSe 2 heterostructures show substantially enhanced activity over MoSe 2 and CoSe 2 in 1 m KOH. The optimal overpotential required to reach a current density of 10 mA cm −2 is merely 218 mV, which is more than 100 mV greater than that of MoSe 2 , which is by far the best performance demonstrated for precious‐metal‐free catalysts. Detailed analyses based on electrochemical testing demonstrate that the water adsorption and subsequent dissociation process is accelerated by CoSe 2 species with rich edge sites; meanwhile, MoSe 2 species provide sufficient active sites for the adsorption and combination of adsorbed hydrogen (H . ). These results provide an effective strategy for developing earth‐abundant catalysts with high activity for the alkaline HER, and are of great significance to promote the practical application of alkaline water electrolysis.