Copper Selenides as High-Efficiency Electrocatalysts for Oxygen Evolution Reaction
Copper Selenides as High-Efficiency Electrocatalysts for Oxygen Evolution Reaction
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DOI：
10.1021/acsaem.8b00746
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发表时间：
2018-08-01
影响因子：
6.4
通讯作者：
Nath, Manashi
中科院分区：
文献类型：
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作者：
Masud, Jahangir;Liyanage, Wipula P. R.;Nath, Manashi
从地球丰富的资源中设计高效的水氧化催化剂在过去几年中引起了极大的关注，因为该技术在几种能量转换装置中具有潜在的应用前景。在过渡金属中，铜是地球上最便宜的非贵重元素之一，由于其大量占据d轨道，可以提高电催化活性。本文首次证明了硒化铜在水氧化反应中的电催化活性。采用直接电沉积法、水热沉积法和化学气相沉积法合成了硒化铜相。通过粉末x射线衍射、拉曼光谱、x光电子能谱和电子显微镜对其结构和形貌进行了表征，结果表明合成的相均为Cu2Se组成的纯硒化铜晶体，具有纳米颗粒结构。在碱性溶液（1 M KOH）中考察了Cu2Se对水氧化的电催化性能，发现Cu2Se的过电位只有270 mV，达到10 mA cm（-2）。该催化剂的塔菲尔斜率也很低，为48.1 mV dec（-1）。有趣的是，无论合成方法如何，Cu2Se都表现出相当的电催化活性，这表明它确实是材料的固有性质。计时安培研究表明，催化剂在超过6小时的连续析氧时间内保持活性，而活性后表征表明，催化活性后结晶度和表面组成保持不变。硒化铜作为稳定的矿物存在于自然界，为高效催化剂的设计提供了新的思路。
Designing high-efficiency water oxidation catalysts from earth-abundant resources has attracted significant attention in the last couple of years owing to the potential application of this technology in several energy conversion devices. Among the transition metals, copper is one of the cheapest earth-abundant nonprecious element which can enhance electrocatalytic activity due to heavily occupied d-orbitals. In this article we have shown electrocatalytic activity of copper selenide for the first time for water oxidation reaction. The copper selenide phases were synthesized by direct electrodeposition on electrodes, as well as by hydrothermal and chemical vapor deposition (CVD) techniques. Structure and morphology characterization through powder X-ray diffraction, Raman, X-photoelectron spectroscopy, and electron microscopy revealed that all the synthesized phases were pure crystalline copper selenide of composition Cu2Se and comprising nanostructured granular morphology. Electrocatalytic performance for water oxidation was investigated in alkaline solution (1 M KOH) and it was observed that Cu2Se showed a low overpotential of only 270 mV to achieve 10 mA cm(-2). This catalyst also displayed a low Tafel slope of 48.1 mV dec(-1). Interestingly Cu2Se showed comparable electrocatalytic activity irrespective of the method of synthesis indicating that it is indeed an intrinsic property of the material. Chronoamperometric studies revealed that the catalyst retained its activity for prolonged periods of continuous oxygen evolution exceeded 6 h, while postactivity characterization revealed that crystallinity and surface composition was preserved after catalytic activity. Because copper selenides can be found in nature as stable minerals, this article can initiate a new concept for efficient catalyst design.