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Mo x C/CNT Composites as Active Electrocatalysts for the Hydrogen Evolution Reaction under Alkaline Conditions
Author(s) -
Yang Fengkai,
Sliozberg Kirill,
Antoni Hendrik,
Xia Wei,
Muhler Martin
Publication year - 2016
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201600269
Subject(s) - catalysis , materials science , carbide , x ray photoelectron spectroscopy , physisorption , molybdenum , amorphous solid , carbon nanotube , hydrogen , phase (matter) , chemical engineering , nuclear chemistry , inorganic chemistry , composite material , chemistry , metallurgy , crystallography , organic chemistry , engineering
Low‐cost electrocatalysts based on highly dispersed molybdenum carbide supported on carbon nanotubes (CNTs) were developed for the hydrogen evolution reaction (HER). The synthesis of Mo x C/CNT was achieved by impregnation using ammonium heptamolybdate followed by a thermal treatment at 700 °C in CH 4 /H 2 , H 2 or N 2 . The composites were characterized by X‐ray diffraction, N 2 physisorption, and X‐ray photoelectron spectroscopy. β‐Mo 2 C was the main Mo carbide phase generated in N 2 or H 2 , whereas α‐MoC was the dominant phase formed in CH 4 /H 2 . All the Mo x C/CNT composites were catalytically active in the HER under alkaline conditions. The catalyst pretreated in pure H 2 exhibited the highest HER activity, which was found to correlate with a higher amount of Mo 2 C, a higher total Mo content and a higher Mo surface concentration compared with the other two less active samples. Amorphous carbon on the surface seems to play an important role in limiting the HER performance of the Mo carbide catalysts, and the treatment in H 2 removed it most effectively leading to high HER activity.