Rational Design and Synthesis of Extremely Efficient Macroporous CoSe2-CNT Composite Microspheres for Hydrogen Evolution Reaction
Rational Design and Synthesis of Extremely Efficient Macroporous CoSe2-CNT Composite Microspheres for Hydrogen Evolution Reaction
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DOI：
10.1002/smll.201700068
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发表时间：
2017-07-19
期刊：
影响因子：
13.3
通讯作者：
Kang, Yun Chan
中科院分区：
文献类型：
--
作者：
Kim, Jin Koo;Park, Gi Dae;Kang, Yun Chan
通过喷雾热解及后续硒化过程制备了具有优化形貌、用于析氢反应（HER）的独特结构的CoSe₂ - 碳纳米管（CNT）复合微球。在CoSe₂ - CNT复合微球中，超细的CoSe₂纳米晶体均匀地修饰在整个大孔CNT骨架上。大孔CNT骨架通过提高电导率以及在合成过程中使CoSe₂纳米晶体的生长最小化，极大地提高了CoSe₂的电催化活性。此外，由CNT骨架形成的大孔结构通过提高生成的H₂的去除速率以及在析氢反应过程中使电极极化最小化，提高了CoSe₂ - CNT微球的电催化活性。CoSe₂ - CNT复合微球在酸性介质中对析氢反应表现出优异的催化活性（在过电位约为174 mV时，电流密度为10 mA/cm²）。纯CoSe₂粉末表现出中等的析氢反应活性，在10 mA/cm²时过电位为226 mV。CoSe₂ - CNT复合微球和纯CoSe₂粉末的塔菲尔斜率分别为37.8 mV/dec和58.9 mV/dec。CoSe₂ - CNT复合微球的塔菲尔斜率比商业碳载铂纳米粒子（30.2 mV/dec）略大。
Uniquely structured CoSe2-carbon nanotube (CNT) composite microspheres with optimized morphology for the hydrogen-evolution reaction (HER) are prepared by spray pyrolysis and subsequent selenization. The ultrafine CoSe2 nanocrystals uniformly decorate the entire macroporous CNT backbone in CoSe2-CNT composite microspheres. The macroporous CNT backbone strongly improves the electrocatalytic activity of CoSe2 by improving the electrical conductivity and minimizing the growth of CoSe2 nanocrystals during the synthesis process. In addition, the macroporous structure resulting from the CNT backbone improves the electrocatalytic activity of the CoSe2-CNT microspheres by increasing the removal rate of generated H-2 and minimizing the polarization of the electrode during HER. The CoSe2-CNT composite microspheres demonstrate excellent catalytic activity for HER in an acidic medium (10 mA cm(-2) at an overpotential of approximate to 174 mV). The bare CoSe2 powders exhibit moderate HER activity, with an overpotential of 226 mV at 10 mA cm(-2). The Tafel slopes for the CoSe2-CNT composite and bare CoSe2 powders are 37.8 and 58.9 mV dec(-1), respectively. The CoSe2-CNT composite microspheres have a slightly larger Tafel slope than that of commercial carbon-supported platinum nanoparticles, which is 30.2 mV dec(-1).