Title: Synergistic-Effect-Controlled CoTe2/Carbon Nanotube Hybrid Material for Efficient Water Oxidation
Authors: Lu, Tzu-Hsiang
Chen, Chih-Jung
Lu, Ying-Rui
Dong, Chung-Li
Liu, Ru-Shi
Master and Ph.D. Program for Science and Technology of Accelrrator Light Source
Issue Date: 15-Dec-2016
Abstract: 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/ cm(2) 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/cm(2) with Tafel slope of 44.2 mV/dec. X-ray absorption near edge structure (XANES) was applied to prove that an electron transfer from e(g) band of CoTe2 to CNT caused a synergistic effect. This electron transfer modulated the bond strength of oxygen-related intermediate species on the surface 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 time dependent 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.
URI: http://dx.doi.org/10.1021/acs.jpcc.6b10000
ISSN: 1932-7447
DOI: 10.1021/acs.jpcc.6b10000
Volume: 120
Issue: 49
Begin Page: 28093
End Page: 28099
Appears in Collections:Articles