Hydrothermal Continuous Flow Synthesis and Exfoliation of NiCo Layered Double Hydroxide Nanosheets for Enhanced Oxygen Evolution Catalysis
Hydrothermal Continuous Flow Synthesis and Exfoliation of NiCo Layered Double Hydroxide Nanosheets for Enhanced Oxygen Evolution Catalysis
复制标题
DOI：
10.1021/nl504872s
复制
发表时间：
2015-02-01
期刊：
影响因子：
10.8
通讯作者：
Jin, Song
中科院分区：
文献类型：
--
作者：
Liang, Hanfeng;Meng, Fei;Jin, Song
本文报道了利用新开发的高温高压水热连续流反应器（HCFR）控制合成NiCo层状双氢氧化物（LDH）纳米板的方法，该方法可以高产率地直接生长在导电衬底上，最重要的是，可以更好地控制前驱体过饱和，从而控制纳米结构的形态和尺寸。利用金属氨配合物的溶液配位化学，在没有拓扑化学氧化的情况下，直接一步合成了定义良好的NiCo LDH纳米板。NiCo LDH纳米片对析氧反应（OER）具有较高的催化活性。通过将LDH纳米板化学剥离成更薄的纳米片，催化活性可以进一步增强，在过电位367 mV下产生10 mA cm(2)的电催化电流密度和40 mV / dec的塔菲尔斜率(1)。这种增强可能是由于增加的表面积和更多暴露的活性部位。x射线光电子能谱（XPS）表明，剥落也引起了一些电子结构的变化。这项工作提出了控制LDH和三元氧化物/氢氧化物纳米结构生长的一般策略，并通过剥离来提高层状纳米结构的电催化性能。
We report the controlled synthesis of NiCo layered double hydroxide (LDH) nanoplates using a newly developed high temperature high pressure hydrothermal continuous flow reactor (HCFR), which enables direct growth onto conductive substrates in high yield and, most importantly, better control of the precursor supersaturation and, thus, nanostructure morphology and size. The solution coordination chemistry of metalammonia complexes was utilized to synthesize well-defined NiCo LDH nanoplates directly in a single step without topochemical oxidation. The as-grown NiCo LDH nanoplates exhibit a high catalytic activity toward the oxygen evolution reaction (OER). By chemically exfoliating LDH nanoplates to thinner nanosheets, the catalytic activity can be further enhanced to yield an electrocatalytic current density of 10 mA cm(2) at an overpotential of 367 mV and a Tafel slope of 40 mV dec(1). Such enhancement could be due to the increased surface area and more exposed active sites. X-ray photoelectron spectroscopy (XPS) suggests the exfoliation also caused some changes in electronic structure. This work presents general strategies to controllably grow nanostructures of LDH and ternary oxide/hydroxides in general and to enhance the electrocatalytic performance of layered nanostructures by exfoliation.