Synergistic-Effect-Controlled CoTe2/Carbon Nanotube Hybrid Material for Efficient Water Oxidation

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• 作者：Tzu-Hsiang Lu ; Chih-Jung Chen ; Ying-Rui Lu ; Chung-Li Dong ; Ru-Shi Liu
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：December 15, 2016
• 年：2016
• 卷：120
• 期：49
• 页码：28093-28099
• 全文大小：407K
• ISSN：1932-7455

文摘

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 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 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 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.