In anode, electrocatalytic water splitting involves oxygen
evolution reaction (OER), which is a complex and sluggish reaction, and
thus the efficiency to produce hydrogen is seriously limited by OER. We
report that CoTe2 exhibits optimized OER activity for the first time.
Multiwalled carbon nanotube (MWCNT) is utilized to support CoTe2 in
generating a synergistic effect to enhance OER activity and improve
stability by tuning different loading amounts of CoTe2 on CNT. In 1.0 M
KOH, bare CoTe2 needed overpotential of 323 mV to produce 10 mA/
cm2 with Tafel slope of 85.1 mV/dec, but CoTe2/carbon nanotube
(CNT) with optimized loading amount of CoTe2 required only 291 mV
to produce10 mA/cm2 with Tafel slope of 44.2 mV/dec. X-ray absorption
near edge structure (XANES) was applied to prove that an electron
transfer from eg band of CoTe2 to CNT caused a synergistic effect. This
electron transfer modulated the bond strength of oxygen-related intermediate species on the surface of catalyst and optimized
OER performance. In situ XANES was used to compare CoTe2/CNT and pristine CoTe2 during OER. It proved the transition
state of CoOOH more easily existed by adding CNT in hybrid material during OER to enhance the efficiency of OER. Moreover,
bare CoTe2 is unstable under OER, but the CoTe2/CNT hybrid materials exhibited improved and exceptional durability by timedependent
potentiostatic electrochemical measurement for 24 h and continuous cyclic voltammetry for 1000 times. Our result
suggests that this new OER electrocatalyst for OER can be applied in various water-splitting devices and can promote hydrogen
economy.
關聯:
The Journal of Physical Chemistry C 120(49), p.28093–28099
